Improving Flexicat’s design and usability

Three weeks ago I posted the design for a card system called the Flexicat, a “universal card system” – a thought experiment about how many game systems can be stuffed into a small deck without overloading it.

It trended on both r/tabletopgamedesign and r/boardgames, resulting in feedback both good and bad.  I’ve taken this feedback and this post shows how I try to improve on all the issues raised. If you haven’t seen it, please feel free to jump to the original design post.

The deck design is so different now that it’s being developed as a totally new system, called the Everdeck. It maintains the Flexicat math while improving the aesthetics and usability of the whole system.   Please follow or subscribe to the BGG dev thread here.

The picture below shows a Flexicat card vs an Everdeck card; this image will be repeated throughout the post to avoid the need to scroll back up.


This post is structured by first a) bringing up an issue, then b) discussing the proposed solution.  I’ve also pointed out c) negative effects from implementing these solutions, with the hope that the benefit outweighs the changes.

Flexicat Problem: Flexicat has 108 cards, so two suits are missing royals. This is confusing, and means it can’t be used to build two full standard decks.


Everdeck solution: Remove wilds, and add royals to increase the deck to 112 cards. This allows the Everdeck to map to two standard decks, a “double standard deck” (e.g. Canasta), or even a standard deck with four distinct suit colors.   This increases symmetry and intuitiveness.


Sacrifice: 112 cards is an awkward number for printing, since it does not match a multiple for print sheets (9, 18, 54, or 55, depending on who you ask).  However, if we need 126 cards for printing purposes,  it’s easy to add a generic “clubs” suit of 14 cards as a bonus.

Flexicat Problem: The “0-100 sequential number” mapping is almost impossible to use.   To use the sequential numbers in Flexicat, you have to “read the suit as a number”, which is difficult to do in hand, and impossible to do on the table.



Everdeck Solution: Add another element, a big number on the upper-right side.  This big number is consistent with the suit-as-number naming convention (e.g. ice = 6th suit; so “62”), but much more practical, both in hand and on the table.


In fact, this number can also be used for a “11 suits x 10 ranks” mapping; for example, above, “62” is the 2nd suit of the 6th rank.

Sacrifice: Will lose the letter at the upper right, which will have to be moved.

Flexicat Problem: The highlighted letter is too small to be of any use for word games.  Also, words with random bold letters look ugly.  Word games benefit from having bigger text, as they’re usually tiled in some central area to spell words.


Everdeck Solution: Highlight the FIRST letter of each card name, make it bigger, then put it at the bottom left side. 


The combination of the number on top and name on bottom calls to mind the design of tarot decks, which also have the number on top and a name at the bottom.


Sacrifice: The letter is moved to the bottom left, which isn’t easy to fan in hand.  This is  a pretty big sacrifice, but something has to be at that corner, and this is the least damaging among all options. But more importantly, this means that we have to….

Everdeck Solution 2: Change the names so that their first letters are distributed in the correct English Lexicon frequency.  Plus, these have to still retain thematic sense within the row and column.  This was a challenge!


Sacrifice: Had to use “The Aeon” from the Aleister Crowley deck instead of the Rider-Waite “Judgement” to avoid the double-J with “Justice”.  “Death” is also frequently called “the card with no name” so that’s where the letter X was stuffed.

Flexicat Problem: It’s VERY confusing to have to rotate cards to play games.   The “small-suit” mapping and “3D card system” mapping require you to play the cards reversed.  The worst offender is the “10 suit” mapping, which requires you to rotate ONLY the royals while keeping everything else upright!

Everdeck Solution 1: The rank and suits are now mirrored both on the upper-left and bottom-right (including the royals) This allows games to be played without needing to sort card orientation.   The royals lose the ability to be rotated, which is more a good thing than a bad thing.


Sacrifice: We lose the “small value” roman numeral on the lower right side (“III” for the hunter), which can be solved another way by….

Everdeck Solution 2: The “small values” on the bottom-right are now drawn as a set of 0-4 black dots rather than as a roman numeral.  (In the example above, the wolf has a small value of “1”.)  The card is also more balanced aesthetically – UL and DR corners show an “icon – number – icon”, while UR and DL corners have big black text.

Notice that the dot coloring matches the color of the card borders – this also unlocks a new tile-laying game system.

Sacrifice: The math has changed, which means dropping the “3x4x5 3D system” mapping.  No one cares about that anyway.

Flexicat Problem:  There is demand to map to a Hanafuda/Hwatu deck (to play Go-Stop/Koi-Koi, etc)

Hanafuda (“Flower cards”) are a set of 48 cards popular in Japan, Korea and Hawaii.  It’s a strange deck: At its core, it’s just “12 suits x 4 unranked cards”, which sounds easy… The problem is that the cards are all categorized and named! There are categories like “junk” and “poetry ribbons” , and it has many uniquely named cards like “boar”, “rain man” and “sake cup”.


Everdeck Solution part 1:  Transpose the deck by assigning months to ranks instead of suits; special categories are classified per suit.  Hanafuda’s 12 “suits” (months) are assigned to the ranks of the Everdeck – so the “January” cards are rank 1, “February” cards rank 2 and so on.


The special categories are assigned to a particular suit. The red ribbons (red, poetry) are on red cards, blue ribbons on blue cards; “Animals” and “Brights” are Gold and Yellow respectively.  All “junk” cards are black.

While some Hanafuda games only care whether a card belongs to a particular category (e.g. “ribbon” or “junk”), the “Animal” and “Bright” cards all have special names.  What’s worse, we can’t just drop these names, since some games give special bonuses to explicitly named combinations of cards,  (e.g. ” boar, deer, and butterfly.”)   How can we now match the Everdeck’s cards to Hanafuda without explicitly drawing those pictures?

Everdeck solution Part 2: Change the deck to an animal theme.  The Everdeck’s animal theme isn’t just for show, but was made partially to match the Hanafuda distribution.  Distributions were pushed slightly to match an appropriate picture to suggest the Hanafuda card name, even if some of them are a bit… weird 🙂


Sacrifice: We lose the cats.  It’s fine. 😦

Sacrifice: How do we know which cards to select if we want to build a Hanafuda deck?

Problem:  Decktet and Hanafuda have weird distributions.  Users will find it hard to remember which cards to comprise which deck without a reference sheet.  Flexicat tried to solve this problem before by adding a diagonal background behind the cat to identify Decktet cards, but it’s inelegant and wasn’t really used anywhere else.

Solution:  Integrate the Hanafuda/Decktet filter into the border system!  By the power of math, we can do the following:

  • If you choose all cards in the deck with a black right border, you get a Hanafuda deck (with a few extra 0s as jokers)
  • If you choose all colored cards in the deck with a black left border, you get a Decktet!

Sacrifice:  People have to remember Right = Hanafuda, Left = Decktet.  (“eastern” and “western” card system, maybe?)


The Lunatic is not part of the Decktet nor the Hanafuda. Remove it.

The result is a system which is nicer-looking, cleaner, and SIGNIFICANTLY more practical.   Many of the loose systems have been dropped, leaving a deck of cards that punches way above its looks.


The Everdeck is a system under continuous rapid development.  Follow its development by subscribing to the BGG design thread!

Contact:, bgg:inaytaobako

Cat icons CCBY3.0 Denis Sazhin; animal icons Saeful Muslim



The Math of Flexicat

This post documents the mathematical properties of the FlexicatAbsolutely none of this information is relevant to the average player.  Basic patterns such as ranks and suits, letters, and names are covered in the previous post.


  1. Small values
  2. Royals’ reverse rank
  3. Secondary-suits
    1. Suits 1-6, Ranks 0-K
    2. Suits 0-7, Ranks 0-10
    3. Paired suit frequencies
  4. Tertiary-suits
  5. Flexicat-Decktet additional properties
  6. Letter distributions

Small Values


  • Ranks 0 and X (10) all have small values of “4”, while the small values from “1” to “3” are distributed from ranks 1 to 9.
  • The sum of small-values per suit are equal.
  • The sum of small values per rank are equal.  This is true whether you sum from suits 1-6 or suits 0-7.
    • Corollary: Sum of small-values for suits 0 and 7 is 4.

Royals’ reverse rank


The reverse-rank of the 18 royal cards form two mirrored magic squares. Side effects include:

  • The sum of reverse-ranks of each suit is 15.
  • The sum of ranks of per type of royal is 30; 15 for light suits, and 15 for dark suits.
  • Each queen has the same reverse-rank as the other Queen of the same color.  Each Jack has the same reverse-rank as the King of the same color.


  • Rank 0 cards have one suit.
  • Rank 1-X cards have two suits.
  • Suits 0 and 7 never appear as secondary-suits.

Secondary suits have different properties, depending on which slice you get.

Secondary-suits: Suits 1-6 from Ranks 0-K


  • The sum of secondary-suits per rank is 28.
  • The sum of secondary-suits per main-suit is 35.
  • For main-suits 1 to 6, each secondary suit appears exactly once or twice per main suit.
    • Specifically, for each main suit, four types of secondary-suit appears twice, while two secondary-suits appear once.
    • The sum of the secondary-suits that appear once per main suit equal 7.

Secondary-suits: Suits 1-6 from Ranks 0-K


  • The secondary-suits 1…6 appear once each per rank.
    • Corollary: The sum of secondary-suits per rank is 21.
  • The sum of secondary-suits per main suit is either 46 or 45, alternating between suits.
  • For ranks 1 and X, the secondary-suit is the same as the main-suit.  For all other cards, the secondary-suit is different from the main-suit.
    • This is a side effect of the Decktet Aces and Tens being single-suited.

Secondary Suits: Suits 1-6 from Ranks 1-X

Decktet introduced the idea of “sympathetic” and “antipathic” suits; that is, combinations of suits don’t appear together with the same frequency.  Flexicat is similar – some suit combinations appear more often than others.


  • The ff. combinations appear 4 times: 1/6, 2/5, 3/4; 1/4, 2/6, 3/5
    • Paired suits (e.g 1&6) appear a lot.
  • The ff. combinations appear 3 times: 1/2, 1/3, 2/3; 4/5, 4/6, 5/6
    • Two of the same light-colored suit, or two of the same dark-colored suit, appear three times.
  • The ff. combinations appear 2 times: 1/1, 2/2, 3/3, 4/4, 5/5, 6/6
    • Ranks 1 and X have the same main suit as secondary-suit.
  • The ff. combinations appear once: 1/5, 2/4, 3/6.


  • All royals and wilds have three suits.  Suits 0 and 7 never appear as tertiary-suits.
  • None of the 18 royal cards have the exact same three suits on them. (order does not matter)
  • Each suit icon from 1-6 (regardless of position) appears exactly 9 times.
    • There are exactly 20 possible ways to choose three suits from six choices, ignoring the order. Since there are 18 royals with unique combinations, there are two missing combinations. The missing combinations are “1, 3, 4” and “2, 5, 6”.
    • The two wilds have the following suits: 0/4/3 and 7/5/2.  If we treat the 0 as a 1 and the 7 as a 6, we get “1/4/3” and “6/5/2”, the two missing combinations!



Flexicat’s version of the Decktet preserves all its existing mathematical properties, and gains additional ones.  This is mostly because Flexicat’s multiple suits don’t always have to be drawn in the same order.


  • Each main-suit has six cards each: an Ace, a Ten, and four cards between ranks 2-9.
  • For each main suit, no secondary-suit appears more than twice.
  • The sum of ranks of the decktet cards from main-suits 1-6 are 32, 32, 35, 35, 32 and 32. [Personal rant: this is REALLY annoying.  There are 16.8 million ways to reduce Flexicat to the decktet, but NONE of them results in a solution where all six suits are all equal to 33.] Even though these aren’t all equal, it still results in some good patterns:
    • Sum of ranks all light main-suits and all dark main-suits are equal. (32 + 32 + 35 = 99 each)
    • Sum of ranks of decktet-sympathetic suits (1-2, 3-4, 5-6) are equal.
    • Sum of ranks of flexicat-paired suits (1-6, 2-5, 3-4) are equal.


Letter distribution percentage, including vowel percentage, was pattered and approximates English and word games. (Scrabble, Words With Friends)



Contact:, inaytaobako@boardgamegeek. Cat icons edited from Denis Sazhin


Features of Fully-Fledged card systems

In the previous post, I tried to categorize features that exist in many existing card game systems.  Some systems, however, are unique or complex enough to not be simply categorized as such.  In this post I try to dig deep into them and explore some of the subtle mathematics of each deck. (featured pic: Glyph)

Jump to links within page:

    1. Decktet
    2. Galloway
    3. Glyph
    4. Green Box of Games
    5. Holydeck
    6. Mesa Playing Cards
    7. Monster Deck 55
    8. Pentology
    9. Rainbow Deck
    10. The Roman Empire
    11. Scroker
    12. Sconudi
    13. Tack
    14. Zont

Continue reading Features of Fully-Fledged card systems

Analyzing game design weaknesses in Card Crawl by Tinytouchtales

Card Crawl by Tinytouchtales is a great concept, combining solitaire, roguelikes, and excellent art into an elegant package. It was casual enough to appeal to a large audience, and the sales figures reflected that.  (IOS link here)

However, I didn’t enjoy playing it.

I tried, I really did. However, it was nowhere as elegant as Scoundrel, the game it says it’s inspired by. I tried looking at its game elements to understand my reaction, and I found several design choices which combine in unfortunate ways.


1. The near-equivalence of all cards.

Despite having a variety of cards, they are all the same under the hood. Monsters reduce your HP. Swords, Shields, and Potions give you positive HP (i.e., reduce negative HP).  Everything can be sold for coins in a 1:1 ratio.  Once you figure this out, winning becomes trivial – it’s just a game of positive and negative numbers. Just imagine your health as a dot moving up and down on a first-grader’s number line and make sure it doesn’t spill off either end (i.e, don’t waste potions).

Here’s the “health impact” of each card in the deck:

Health Chart

Without special cards and without selling anything, you will ALWAYS win with 2HP. If you do a single reshuffle (costs 5HP), you die. If you sell a single Shield(3), you die.  How can people even be losing this game? Why are there people commenting that it’s “tough and addictive”?

2. The game has zero decisions relating to the basic cards.

Once you understand the numeric equivalence of the basic cards, Card crawl turns into a non-game. Me and everyone I know who realizes this (or I explained it to) has win rates of 90% and above, marred only by bad spreads (which you can’t control).

3. The only cards relevant to your score are special cards

Since the basic cards are deterministic, they’re useless when it comes to improving your score.  With only 5 special cards in your deck, much of the game is spent juggling and positioning the other cards to make use of the specials.  Which wouldn’t be so bad except…

4. Some special cards are obviously much better than others

… The special cards are also wildly varying in power! It’s also insultingly easy to calculate the risk-benefit ratio of special cards; compare these two, which are both used in the same way (when you are at low health).  Why would I ever use the first one?

  1. Sacrifice (deal damage to a monster equal to your missing health) – 1 to 10 points net gain
  2. Blood Pact (pictured) – Gives you 0 to 18 points (if you swap at 1 health with a 10 health monster)


Some cards, like Sap (push back a card into the deck) and Vanish (redraw all cards) actually give you a zero point swing, making them useless for improving your score.   This means there are only a few cards that you would ever think of using to get a high score in constructed, and…

5. The game is solvable, but getting the highest score becomes a question of luck instead of skill.

…To get a high score in Constructed mode,  I’ll get the highest potential gain cards (e.g. Morph, Midas, Swap, Betrayal, Lash or some other powerful ones) and just start praying to RNGesus.  No skill involved, just hoping that the cards are dealt in the correct order.

6. Counterintuitive unlock scheme to get high scores in Normal mode.

Furthermore, to get a high score in Normal mode, where special cards are randomly chosen, you have to NEVER UNLOCK any of the weaker cards (so they do not get added to your random pool.).  Just grind to get enough money using the basic cards, and only unlock the specials with a high potential life swing.

7. The difference between an “ok” score and a “high score” isn’t all that large.

But is it worth it?  The difference between the theoretical highest score (something like 150) and my normal score (120)  isn’t, you know, all that much.


I hope I wasn’t too harsh on the game.  It is actually quite good as a diversion for the first couple of hours; art style is excellent, and the quests are much, much more interesting than the basic game.  But when your core loop can so easily be dissected and broken down this easily, it had nowhere near the staying power I expected.  I can’t help thinking that maybe there should be a little more to crawl into.

Cellsweeper.xlsm: Dungeon Crawler RPG based on Minesweeper


New game is Cellsweeper.xlsm, a dungeon crawling RPG. The link below contains two files – the Excel itself and the “Cellsweeper” font. You could play the game without it, but it would depend on your tolerance for fighting alphanumeric characters instead of monsters. 🙂

Here’s a link to the game – Cellsweeper 1.1 (last updated 9/2/2015)

v1.1 Changes:

  • Fixed the assassin bug that hurts you for every cell opened if you mis-backstab on a wide open space
  • Emphasized that backstab only works on monsters of the *exact* same level

Design Notes:

The game is inspired by Mamono Sweeper, and attempts to improve some design elements in Mamono I didn’t like:

  1. The game is a bit too abstract.  
    • I felt that the game didn’t fully embrace the “RPG” aspect, and could easily be an abstract minesweeper version with multiple mine levels.
  2. The difficulty curve is reversed.
    • Since there are many more low level monsters than high level ones, it starts off hard and becomes easier at the end, not the other way around.
  3. There’s no point to the level 1 monsters.
    • It’s obvious that the player can immediately click on any cell adjacent to a “1”, and it just costs the player additional clicks.
  4. The game becomes rote at player level 5 (and to an extent, 4).  
    • At high levels, it becomes clear which cells are clickable, giving the last part of the game less tension. The game ends on a low note by having to click all remaining cells.
  5. The “Second click” problem
    • The first cell is always free, but the player can frequently get a huge damage hit on the second click.
    • Also, players usually play by jumping around for the first few clicks to try to open a large space.
  6. A cell with a monster also has a helper number “underneath” that monster.
    • It’s frustrating to keep switching between the “number view” and the “monster view”, since the cell can’t represent both at the same time.
  7. The player has to keep referring to the legend to remember the monster levels.
  8. There’s little replayability once you’ve figured out the optimal strategy.


For Cellsweeper, I tried to tie my solutions to a strong “dungeon crawling” theme.  I find the result much more fun to play (hopefully you do too!):

  1. Difficulty curve:
    • When the hero levels up, there’s a 50% chance for weaker hidden monsters to level up as well.  The difficulty curve is now balanced – the player first explores an “easy” area, with the areas becoming more difficult as he becomes stronger.
  2. Little point to level 1 and level 5 monsters
    • Introduced a win condition: The player wins by defeating the necromancer, not by clearing out the board.
    • Fighting an enemy of the same level also damages the hero.  This means that bats (LV1) pose a threat at the start, and wraiths (LV5) are still a threat at max level.
    • The hero gains XP from exploring the dungeon.
  3. “Second click” problem:
    • The player can only explore cells adjacent to open ones, like a hero navigating an actual dungeon.  This also prevents information overload, as the player only concentrates on small parts of the map at a time.
    • The first cell is automatically selected for the hero and is always a “1”.  This prevents him from cavorting off and getting killed immediately.
    • Changed borders to look like the player is “carving out” the dungeon.
  4. Helper number underneath the monster
    • Removed this feature.
  5. Need to keep referring to the legend
    • Monsters are color coded with increasing color warmth; the legend is still needed, but it’s a bit more intuitive.
    • Originally, I thought of adding a subscript to the monster showing its level, but was worried that players might confuse this for a helper number.
  6. Replayability
    • Added high scores.
    • Added multiple character classes with different abilities – three basic characters (fighter wizard rogue), and three “advanced” classes (barbarian monk assassin).
    • Significantly tweaked the difficulty of the classes – now people of different skill levels can play.