The Sylladex is the inventory system in Homestuck. Most player-controlled characters have a Sylladex to store and retrieve artifacts from, which consists of two decks of cards: the Captchalogue Deck and the strife deck.
The word "sylladex" is presumably a portmanteau of "syllabus" and "index"; its plural is "". It's also possible that it's parodying the "Pokedex" from the Pokémon series.
None of the Exiles have a sylladex, so they must always carry objects in their hands. While Midnight Crew members do not have a Sylladex, their inventory allows them to hold five weapons and one item (all members use a Deck of Cards/Storage Item to work around this rule). This inverts Problem Sleuth's inventory system of five items and one weapon.
The word "captchalogue" is a portmanteau of the words "captcha" and "catalogue". The word "captcha" hints the codes on the back of each card.
The Captchalogue Deck is where artifacts are stored to be used later. Artifacts of any size and shape are stored on Captchalogue Cards, and while stored, they have no physical size or weight (so while John Egbert is unable to actually use a Sledgehammer on his own, he is still able to carry it around in his Sylladex), making the Sylladex much like a bag of holding.
Some sylladices can store larger objects than others, as seen, where John's Dad stored ten tons of tobacco and a car, among other things. John later stored The Tumor there.
However, there is a limit to how many different items can be captchalogued, based on the number of cards in the character's deck. Captchalogue cards can be added to the Captchalogue Deck by captchaloguing them and then forcing them out of the deck by doing something like adding an item, which at least the Stack deck will react to by putting the item into a card that holds the card the user is trying to add to their deckmain arc number of the comic.. Once a player has too many cards to line up side-by-side on the screen, the cards are arranged in stacks. Early on, John's deck is arranged in thirteen stacks of four, mimicking the suits and ranks of playing cards (which, like captchalogue cards, come in decks) as well as the
Also, living things can apparently be captchalogued, however it is unknown what it feels like to be inside a captchalogue card. It is also unknown if a person can captchalogue themselves, though this would probably be unlikely, since doing so would create an infinite recursive loop due to the captchalougue card being held by the player, who is stored in the card.
Sylladex users are capable ofif more than one is contained within it.
Punched Captchalogue Card
Punched cards are captchalogue cards that have been punched using the Punch Designix. The items stored in these cards can't be retrieved, but they can be duplicated using the other items from the Phernalia registry. To use a punched card, one must place it in the Totem Lathe to carve a Cruxite dowel into a totem unique to that card. That totem can then be used in the Alchemiter to re-create the object on the card, as long as one has the required grist.
One punched card, called a pre-punched card, is available in the phernalia registry at the beginning of Sburb. John Egbert created the Cruxite Apple, Rose Lalonde created the similar Cruxite Bottle, Dave Strider created a Cruxite Crow's Egg, and Jade Harley created a Cruxite Dog Piñata.
Items can be combined by overlapping cards, thus obscuring some holes (like a bitwise AND operation) or by punching one card with both items' codes (like a bitwise OR operation). It appears that the operation used only determines which item used is the primary one, as seen with the Pogo Ride and the Sledgehammer; overlapping cards created a Pogo Hammer whereas double-punching a card made a Hammerhead Pogo Ride.
It appears that combining items rather than cards (i.e. drawing on a poster with crayon) still changes the item's code, similar to how the code would change if you simply combined the cards.
The fashions in which artifacts are stored to and retrieved from the Sylladex depend on the currently active Fetch Modus. The active Fetch Modus can be chosen as long as the Sylladex has the card with the desired Fetch Modus. Each Fetch Modus has a unique color given to all Captchalogue cards in a Sylladex that uses it. When outside of a Sylladex, Captchalogue cards are red. Each Fetch Modus is more different from the last: some Fetch Modi are based on data structures, some are based on popular board games, some are just mundane, like Dad's, which is a wallet, or the trolls', which are hard to fit into a single short sentence.
The back of a Fetch Modus stores the options menu, which can be used to modify the Modus
Humans' Fetch Modi
John Egbert's first Sylladex Fetch Modus, signified by a bright magenta Sylladex and matching Captchalogue cards. Captchalogue cards are arranged in a stack, and the player can only use or otherwise interact with the one at the top of the stack. The top card may also be combined with the previous card if doing so is logical (or if the objects can be physically forced into one another), or use it with the previous card. If an object is picked up while the Sylladex is full, the item at the bottom of the stack will be dropped.
Interestingly, when Dave asked John how he retrieved things, John replied "one at a time i guess. and if i put too much in, something falls out." Not only does that have little relevance to Dave's question, but Dave was also able to identify Stack from this description, even though it could've applied to just about any other Modus. Though, this may be because it is a snarky answer avoiding the question, and if he was using something more interesting, he would have actually answered it.
This fetch modus is based on the stack data structure.
The second Fetch Modus John obtains, signified by an orange Sylladex and matching Captchalogue cards. It is essentially the opposite of the Stack, in that only the card at the bottom of the deck (the one that was added before any of the others) may be used directly.
Though John had a separate card for his Stack and Queue Modi, they were identical cards with different settings, since John could switch either card to fulfill either Modus. He later combined the two with the Modus Control Deck, thus allowing him to draw cards from either side of his "Queuestack" without the inconvenience of having to switch his Modus type back and forth.
This fetch modus is based on the queue data structure.
The third Fetch Modus John obtains, originally intended as a birthday present from Dad. It is light blue in color. It supposedly allows John to fetch any card at will. John considers this to be excessively boring because it cannot be weaponized, however, and uses the Modus Control Deck he obtained from Dad's Room to combine it with his Queuestack, thus creating an Array of four 6-card Queuestacks. While more amusing, John actually makes his fetch modus more limited than just the Array alone.
This fetch modus is based on the array data structure.
John uses the Modus Control Deck to combine his Stack, Queue, and Array Modi. It does seem much more interesting to use than an Array modus, but has less accessibility to captchalogued items. The way this Modus works is it divides all the captchalogue cards into 4 arrayed Queuestacks with 6 cards each. From there, John can take a Card from the first or last card from any of the Queuestacks.
Rose Lalonde's Fetch Modus, Trees, is signified by a lime green Sylladex and matching Captchalogue cards. She admits that it isn't exactly practical but initially considers it elegant. The first item is captchalogued in the Root Card. Any more items that are picked up are Branches attached to an existing card and, like the root itself, may have up to two branches of their own (making this a binary tree). Branches with no further branches of their own are called Leaf Cards. Cards are sorted alphabetically: they join the left branch of an existing card if they come alphabetically before that card, or the right branch otherwise. Nothing has been shown to demonstrate what happens if she has two identical objects. The only cards Rose may access are the root or leaf cards; intermediate branches can only be accessed by moving them to the root or leaf positions via the optional auto-balancing feature, which (like an AVL tree) rearranges the tree whenever it becomes too unbalanced. If she uses the Root Card, all of the items below will fall out of the sylladex, which is why she has set it to Leaf instead of Root.
Since Rose never captchalogues more than her cards can hold, we are never shown an object being forced out of her deck or more cards being added to it. This fetch modus is based on the binary tree data structure.
Dave Strider's Fetch Modus, signified by a yellow Sylladex and matching Captchalogue cards. Hash maps work through a key-to-value lookup structure, making the Hash Map Fetch Modus the most like a traditional inventory. Each card in the deck is given an index from zero to the number of cards in the deck minus 1 (10 cards leaves an index range of 0 to 9). When an item is captchalogued into a Hash Map Sylladex, where it is placed into the card stack depends on the current Hash Function. If an object already occupies the card with the produced index, the item in the card is ejected from the Sylladex to make room for the new item. In order to retrieve an item from the stack, the character must perform an action related to the item with a keyword that will produce the same index as the card that holds the desired item. Items apparently are retrieved so long as a relevant command with an equivalent hash is uttered, regardless of Dave's actual desire to use the item. If the objects are retrieved this way, they are thrown out as if another item was placed in their card. Dave once by yelling "stop" (hash 7) at it, killing it. Dave's reaction implies this was not intentional. The force of which the item ejects from the Sylladex may be related to how much emphasis is used on the command.
On the back of the fetch modus card are several options. One of them, a "potentially dangerous button," ejects every item in the Sylladex. Another option allows the user to change the hash function used to calculate indexes, though changing the hash function will eject all items too. A final option is a check box labelled 'detect collisions' which originally was unchecked. Now that it's checked, Dave is prevented from captchaloging an item when doing so will cause another item to be displaced and ejected, making captchaloging slower but safer.
It is notable that objects that are captchalogued don't have a set name. For example, Dave captchalogued multiple Shuriken (3) one at a time to avoid dislodging a Box (5) he had filled with Fireworks (5). This is after he spilled the Box of Fireworks (3) by replacing it with Nunchaku (3). Items that share the same index can be combined even if the combined name of the items wouldn't equal that index.
Dave later replaces this modus as a whole after his alternate future self. This one is orange with yellow vertical stripes on the left side. It's unknown what the modus actually is, but considering the number of cards Davesprite left Dave, and how easily he uses it, it's suggested to be something far less annoying; based on the colors, it could be a hash map combined with a series of queues to resolve collisions, which is how hash maps are usually used in the real world.from
This fetch modus is based on the Hash Map Data Structure.
- The hash function Dave uses most often gives each letter in the word of an item's name a value (2 for consonants and 1 for vowels), adds the numbers up, and divides the sum by the number of Captchalogue Cards in the deck. The index is the remainder. The letter "Y" can be used as either a consonant or a vowel, but only a hashmap noob would use such a cheap trick. (Dave has used this "cheap trick" at least once.)
- Another hash function switches the values, making vowels worth 2 and consonants worth 1.
- A third function gives letters their value based on the order they appear in the alphabet. (A=1, B=2, C=3, and so on.)
- Dave programs a fourth function in which each letter's value is the same as the letter would have in a game of Scrabble. Specifically, A=1, B=3, C=3, D=2, E=1, F=4, G=2, H=4, I=1, J=8, K=5, L=1, M=3, N=1, O=1, P=3, Q=10, R=1, S=1, T=1, U=1, V=4, W=4, X=8, Y=4, and Z=10.
Jade's Modus Set
Jade Harley has a whopping twelve Fetch Modi, which comprise the Modus Set that her Grandpa bought her for Christmas. All twelve of these Modi are based upon popular board games. Judging by the official product logos and trademark symbols, it is highly likely that these Modi were licensed by the same companies that made the games in question (at least in-universe), and therefore can only be obtained via purchase.
The fact that these Modi are based upon board games rather than data structure is consistent with Jade's silly, playful nature and her apparent lack of interest in serious computing.
Jade also has a large number of Captchalogue cards. She has 52 cards (the number of cards in a standard playing card deck), and when she has no Fetch Modus selected, they are arranged into thirteen stacks of four.
Based upon the beloved game of matching pairs of identical cards, this is Jade's preferred Fetch Modus, due to her powers of precognition. This Modus uses an even number of captchalogue cards, which are purple. When an object is captchalogued, it is placed in the next empty slot to the right. If the sylladex is full, the leftmost item isFor retrieval purposes, a captchalogued item is stored in two random cards. In order to access an item, the two cards in which that item is stored must be selected, and it appears that all item positions are randomized when an item is captchalogued. For most people, this would be troublesome to say the least, but for the reason stated above, this Modus is perfectly suited to Jade. Also, her silly, playful nature causes her to flesh out her Sylladex with simple, brightly-colored objects (such as fruit, as we have seen), causing it to more closely resemble a child's card-matching game. During the fit of pages where the wrong items are selected (Mostly fruits), one has to understand that it's not Jade making the choices as she gives the reader control, while giving "hints." These hints were actually 100% correct, while the reader was a dumbass and picked elsewhere regardless.
Based upon the nervewracking game of manipulating precariously-placed blocks, this Modus uses eighteen captchalogue cards, which are dark blue and violet. When the Modus is selected, it spawns a Jenga tower made of 54 Captchalogue Blocks (54 being the number of blocks in a standard Jenga tower). Each item, when captchalogued, is assigned to three random blocks in the tower. To retrieve an item, its three blocks must be removed. When an attempt is made to retreive a specific item, its blocks are highlighted. If the tower is toppled, all items assigned to completely toppled trios of blocks will be ejected. This system appears to be extremely unwieldy, due to the likely difficulty in moving the tower. Also, while unknown earlier, Vriska practices putting Jade to sleep, making this Fetch Modus completely useless to her.
Jade chose this Fetch Modus based on a strong whim from the Eclectic Bass., which is a fancy way of saying that Andrew put it to a vote. Its cards are mossy green. When selected, this Fetch Modus spawns a Captchalogue Scribblepad. Drawing a nearby item on it results in the captchaloguing of that item. Even if the drawing is a meaningless scribble, the Scribblepad will associate it with an item. If the Captchaloguing of an item that is not nearby is attempted, a ghost image of it will be captchalogued instead. Ghost images are unusable but have the same Captchalogue codes as their real counterparts, enabling a Sburb player with access to alchemical equipment to create them. (And, theoretically, any item that the player can draw can be created.) It seems to have a bit of trouble identifying drawings of overly simple or overly complex things, such as Jade's Tangle Buddies and her
Nepeta Andrew Hussie is also seen using a Captchalogue Scribblepad as a graphics tablet in his into the story.like Jade's as a computer, but is explicitly stated to not use the Pictonary modus, using something implied to be far more frustrating instead.
This modus is apparently capable ofwithin a card, but presumably only because Jade shrunk them first.
The author commentary in Homestuck Book 3: Act 4 notes that the Scribblepad wants to assume the artist is drawing a robot whenever it tries to parse something mechanical-looking, and that it's likely the Scribblepad has an AI and is wanting the artist to build it a friend.
Unused Fetch Modi
The nine other game-based Fetch Modi have yet to be seen in action. Their names and postulated functions are as follows:
Boggle: The symbol for the modus says "Boggle Fetch Modus" in a snaking pattern on the Boggle grid. A possible speculation of its use is that the user has to find the name of the desired item in a Boggle puzzle. It could possibly randomize the name, since items do not have a set identity, i.e. a dollar bill may become a monetary note.
Monopoly: It might be possible that this modus has 12 cards (Monopoly having 2 dice, meaning that the maximum number would be 12), and rolling a pair of dice would assign an item to a card. This could possibly build a "house" on the card, and if you roll the same number for the card for another item, it could be possible for the item to go to the "Go" card (This one being card number one).
Yahtzee: One can logically deduce that one has to roll a set that corresponds with a code assigned to a card: think Hash Map values with dice. For example, a lime may correspond to rolling a single pair, while an orange may correspond to rolling a full house. More important/powerful or otherwise less redundant items are likely given higher set values to attain.
Clue: It possibly works as follows: The desired card is split up and placed in the "envelope" of the modi. The card fragments, or 1/3cards, correspond to a Suspect, Room, and Weapon. The user is given some cards, but the remaining cards are split five ways, invisible to the user. In order to remove the item from the "envelope," one must successfully enter all corresponding values for the item: for instance, retrieving the Eclectic Bass by naming "Professor Plum in the Library with the Wrench" (Professor Plum + Library + Wrench). This would require either precognitive ability, which suits Jade, or an exhaustive process of suggesting and eliminating every other possible value.
Connect Four: It could operate by splitting the cards into four pieces and then providing the user with random game pieces, one at a time. The item would then be retrieved by connecting the four corresponding fragments of the item.
Battleship: It's plausible that an item would have to be retrieved from the modus by sinking the ship that corresponds to the item desired. This would require precognitive ability, which suits Jade.
Ouija: Is listed below in its own section. May function slightly differently to Aradia's version, probably with English letters.
Guess Who: It possibly works as follows: The cards are scattered on the Guess Who board. The Modus likely picks a random card and the user has to try and guess it to retrieve it, with the Modus providing clues and answering the user's questions to help them find the correct answer.
Operation: This one is likely very straightforward: extract the cards without touching boundaries provided by the modus. (different editor: i also imagine if you touch any boundary, either all items will be ejected, or the player will simply have to try again, but this just speculation)
Dad's Fetch Modus, signified by brown Captchalogue Cards (the same shade of brown as the Clue Fetch Modus). It stores Captchalogue cards in a wallet, and any card can be at any time. It functions similar to a normal wallet and is refreshingly uncomplicated. It is more or less the Array Modus without size restriction, and with tangibility, meaning the entire Sylladex can be passed from person to person. The Modus component seems to be bound to its physical wallet counterpart. When John finds it, he discovers that this Modus has, in addition to an 'eject' button, a 'polish' button , undoubtedly for effortless polishing of the wallet.
The cards of this modus are able to store car that it contained is significantly larger than the harlequin doll, which John couldn't captchalogue with his previous modus, as well as the Tumor, which is so incredibly ginormous it's almost not funny. On second thought, it is. Jane also used her Dad's wallet to store an entire mirrored obelisk temporarily, before realizing she needed it to open a door, while Vriska eventually uses a modified version of this modus to store the entire planet earth.of objects in single cards, as well as incredibly ginormous things - the
Because it could be passed from person to person, John's Dad's wallet has a somewhat convoluted history. After John found it at the scene of his Dad's death, he used it to store the Tumor and gave it to the Wayward Vagabond to deliver the Tumor to Rose and Dave. However, it was stolen by the Courtyard Droll; the card containing the Tumor was stolen back by the Bunny, but the Courtyard Droll kept the wallet itself and used the shaving cream inside to kill Jade Harley, only to get himself killed in turn by Jack Noir. Jack stuffed the wallet into Lil Cal and later threw both at an Aradiabot, which went back in time to later be found by a much younger Aradia Megido; what happened to the wallet after that is unknown, but Terezi Pyrope indicated in her instructions to John that it was important and instructed him to deliver it to her alternate self, which John (having lost it three years ago) was unable to do.
Jane Crocker's Fetch Modus, signified by red Captchalogue cards and a white Betty Crocker logo on the cartridge. It is a fairly new experimental innovation. Anything captchalogued will be added to a recipe book. Flipping the card, instead of showing the item's captchalogue code, shows a 'recipe list' of what items could be combined to alchemize it (it is noted in the story that the recipe framework is completely theoretical, since, at the time, Sburb, with its alchemy system, was yet to be played). Other than this, it seems to function identically to the Array Modus. It's worth noting that different recipes on the back of the same card have vastly different grist costs. This could mean a number of things - either different combinations resulting in exactly the same item have separate costs, or the recipes are actually for different variations of the item instead of being for the exact object and captchalogue code on the card. Perhaps even that the codes themselves are just one variable in determining the content of the card, and the amount/type of grist is also counted (explaining how the Gristwidget is able to recycle stored items; consider that combining two items results in the same code as combining two other items, yet results are different because of differing proportions of grist cost. The scale of grist cost is then used to determine the item's size). The modus also allows the user to captchalogue several items at once.
The Recipe Modus itself is alchemizable from the Array Modus and the Cook Book, and costs 11 units of Build Grist. Jane's Dad got her the Recipe Modus for her birthday.
One of Jane's old Fetch Modi. Its functionality is unknown, as it was only mentioned in passing as a rather impractical modus, although there is a real life Fibonacci heap data structure.
Jake English's Fetch Modus. Signified by blue Captchalogue cards, it can store items of any size, turning them into cards of various sizes which Jake must then rearrange in order for them all to fit properly. If they do not fit, naturally, the items that do not fit are ejected. Until recently, the majority of the modus' space was taken up by the remains of his house.
Message in a Bottle
Roxy Lalonde's Fetch Modus, signified by light grey Captchalogue cards. The modus shrinks the cards, storing them in grey bottles similar to Rose's Cruxite artifact, and then stores the bottle in a large grey cabinet. The object in the card is released by smashing the bottle containing it.
It should be noted that when Roxy attempted to captchalogue paradox ghost imprint slime, the modus did not store the slime in a card beforehand, but put the slime into a bottle instead. We are not sure if this applies to all liquids or just ghost slime; but it is definitely useful for Roxy.
Dirk Strider's Fetch Modus. The cards in this modus are black with grey and orange stripes. The way this modus organizes items is by placing them into grey Shade Columns and orange Groove Rows. All items in a Shade Column must rhyme in some way (such as "GameBro" and "Faygo") and all items in a Groove Row must have some thematic similarity (like a weapons row or a 'cool bros' row). There are ways it can be used for rap battles much like Hash Map (and Dirk successfully utilizes it in such a way in a battle with Squarewave), but it is a little more sophisticated and complicated. Its name and function are based on And It Don't Stop, an older comic by Andrew Hussie about rap and robots.
A Fetch Modus mentioned offhandly by Dirk. It is mentioned alongside Hash Map, as both are employed by traditional hashrap artists and are more involved with numbers, while Tech-Hop, which is used by advanced hashrap artists such as Dirk himself, is more involved with rhymes, which are an actual skill required in rap.
The nature of the Hash Table modus is unknown, but some conjecture can be made, based on the Hash Map modus and the corresponding data structures: While a hashmap stores key/value pairs (being a string of letters and an item for the Hash Map modus), a hash table only stores values, and does not need a key to pair with values. Likewise, the Hash Table hashes the item being stored, rather than the key used to represent it. Therefore, retrieving an item already in the table does not need the key to be hashed a second time: instead, the index of the item is used directly. As a result, the Hash Table modus likely works similarly to the Array modus, except that each item can be inserted only into one specific index (and, presumably, is more easily weaponized).
Trolls' Fetch Modi
Karkat Vantas' Fetch Modus, signified by grey Captchalogue cards. When an item is captchalogued, a card safe (with a weight possibly invariably greater than that of the item captchalogued) is produced. To retrieve an item, you have to hack the code to open the card safe. Since the safes become physical objects, the very obvious drawback to this modus is the inability to take the safes with you; they just end up recaptchalogued into a (perhaps guaranteed heavier) card safe. Supposedly, Karkat eventually swaps modi with Sollux, who naturally is better suited to cracking codes (and, being telekinetic, presumably can carry the heavy safes around just fine). While this modus causes the item to be secure against thieves and other ne'er-do-wells, it is not necessarily safe, especially from .
Aradia Megido's . The spirits decide what item is retrieved, leaving Aradia with little or no control as to what item is retrieved. However, it perfectly suits Aradia and her fatalistic beliefs as she does things based on the voices she hears. The 'spirits' tend to be a little cryptic, for example showing 'Bing' as she retrieves the Crosbytop. On Earth, the planchette is supposed to highlight the letters with its lens.
Gamzee's and Kurloz Makara's Fetch Modus. By far the most complex and confusing Modus ever seen, Gamzee has absolutely no idea how it works, and doesn't want to know. Most of the time, he would captchalogue an item only to watch the colors that the Modus produces.
The Modus seems to work a bit like two of the seen Jade's Modi, Memory and Jenga, in the fashion that it stores the captchalogued item in multiple cards. However, it is complicated by the fact that the cards themselves have seven colors: teal, green, orange, brown, blue, yellow and citrine, and the Modus seems to only use one card (if any) of each. When retrieving an object, the sylladex can eject an item from a seemingly random card very, very far. These are most likely not its only functions. It has been noted that successfully retrieving the item you want with this modus can take a miracle. Despite outward appearances showing this modus to be exceedingly complex, it has the potential to be the most useful modus of all. After having his soda chucked across the entire troll ocean, Gamzee is shown to be able to simply reach into one of the cards and take the item he wanted (Though this may just be Gamzee, of all characters, to even ponder the thought as most other people are confused by practical thinking, such as
Kanaya Maryam's Fetch Modus, signified by light grey Captchalogue cards. This Fetch Modus locks up the item, rendering it impossible to use unless the corresponding Auxilatrix Key - which seem to be physical objects rather than simple abstractions - is . The keys themselves are locked in a chest, at exactly when and where Kanaya is predestined to use the item. Obviously based on the chastity belt (fitting in with her being the Virgo troll), as the key will only be found when and where Kanaya is ready to use the item. The modus releases the Matriorb so Eridan can destroy it, indicating it was never meant to be hatched.
Vriska Serket's Fetch Modus, signified by black Sylladex cards. Unusually (but understandably, given their function), the portions of the cards where objects are normally displayed is blue. Although this Fetch Modus has never been explained or even named, its method of functioning is clear. When an object is captchalogued, it is sealed within a Magic 8-Ball. Presumably, releasing the object involves breaking the ball that contains it (explaining the many broken 8-balls in Vriska's room). Shaking the ball and looking at the "answer" merely reveals the code. The was written very clearly, with only a solid blue background color, white stripes, and white text. It's possible that all captcha codes are rendered as such with this modus, and therefore made easier to read.
Upgraded Eight Ball
Using the captchalogue code for the Wallet Modus, Vriska. The new modus uses brown transparent 8 balls (due to the resemblance to , it's possible that the upgrade process may have also included a crystal ball). Like the wallet modus, it can captchalogue extremely large items, and it is used to captchalogue the Earth.
Scratch and Sniff
Terezi Pyrope's Fetch Modus signified by multicolor striped cards, vertical pink and purple on the left, and horizontal darker purple and blue on the right, looking similar to a modus constructed with a Modus Control Deck. The modus apparently allows any item to be retrieved with a thought at any time, but the items can only be identified and selected via smell. It's likely that Terezi randomly chooses cards and guesses which one has the object she is looking for. This works quite well for Terezi due to her uncanny ability to smell colors.
Other Fetch Modi
Unique to Calliope and Caliborn, whenever one of them captchalogues something it becomes only accessible to the other. The cards are marked with cherry red and lime green. After Caliborn takes full control of the body, the modus is to only be in two shades of red. This may be a reference to not only his blood color, but also his role as a Lord of Time, or may simply be the result of no longer having a second party to make it exclusively accessible to.
In Hiveswap all playable characters (thus far Joey Claire, Jude Harley and Xefros Tritoh) use the same kind of Fetch Modus, which has green cards (with slightly different shades depending on whether the character is on Earth or Alternia) although Jude had grey cards in early development footage. As by the lead writer, for the purpose of convenience to you, the player, these Modi do not have ridiculous restrictions or awkward rules unless examined in detail, instead working like a typical adventure game inventory. It is still a sylladex, though, as the characters will on occasion refer to captchalogue-related terminology.
It has three distinct portions. The main portion on the left can store any number of items (and will appear to generate captchalogue cards as more items are stored), and its items can be used with any other item or any background detail, giving it the functionality of the Array Modus with a potentially unlimited number of captchalogue cards. However, they are not dropped at will by the player, only when the characters themself choose to; As the items picked up become relevant later during the plot, dropping them at any time would be frustating. To the right of the main portion is the Techniche, the Hiveswap equivalent of the strife deck where Abilitechs are placed, and further to the right is a single slot which only stores communication devices, such as walkie-talkies and tablets.
The captchalogued items can be automatically transferred to other slots if functional for the purpose: when Joey picks up her walkie-talkie and its batteries separately they appear in her main sylladex, but when combined and the walkie-talkie is powered it immediately moves to the communicator slot. Her flashlight is stored in the Techniche slot even before she finds the batteries for it, but Joey can use it as a blunt weapon in a maneuver known as "Pirouette and Bop", which does not require it working to be used as a weapon.
The communicator slot can drop items involuntarily, as Joey does not carry her Walkie-Talkie from Earth to Alternia despite never purposefully dropping it. It's likely her communication device would not work there anyways and was therefore automatically dropped from the slot.
The game is programmed in such a way that only three Abilitechs can be stored and used at will in any character's Techniche. However, as the item associated with the Abilitech will disappear even if it isn't properly picked up, this likely isn't intended behavior.
In Homestuck^2: Beyond Canon (Dubiously Canon)
Used by Dirk Strider, little is known about this modus.
- Andrew Hussie. "The Scribblepad really quite enthusiastically wants to assume you're trying to draw a robot any time you draw something mechanical-looking it can't parse. I think this makes it likely that the Scribblepad is a pretty sophisticated AI, with a whole personality and such. It just really wants you to build it a friend. :(" Homestuck: Book 3: Act 4, p.140. October 25th, 2018.