NOTE: Entry in "Contest X 2019" Please comment on the rules in the discussion on BGG
In a corner of your fridge there is a hidden menace.
Well, actually it's not hidden anymore.
Small spots of mould have appeared, slowly growing and spreading across the sandwich you forgot in there a week ago.
Which one of them will eventually win out, absorbing the others and cover most of the sandwich?
Set up the board as shown in the photos below.
- Use 36 tiles for the 6x6 grid square board, or 34 tiles for the quasi-triangular board . Align the tiles correctly for the quasi-triangular board, it helps for seeing the hexagonal pattern.
- Each player uses 20 wooden cubes in their chosen colour. In some game variants a player might need more than 20 cubes, if so you'll figure out something
The starting player is decided by the player that last found some mouldy food in the fridge.
Square board - 2/4 playersEdit
Play with 2 or 4 players on the orthogonal square-shaped grid (using 6x6 tiles).
- With 4 players, place one cube in each corner, as shown in the photo above.
- With 2 players, place 2 cubes of each colour on the board, each colour in two opposite corners.
Quasi-Triangular board - 2/3 playersEdit
Play with 2 or 3 players on the quasi-triangular hex-symmetric grid (using 34 tiles).
- Place 3 cubes of each player colour on the board; 1 in the corner and 2 on the recessed tiles in the middle of the opposing side.
- With 2 players just remove one of the colours.
- There can be only One (cube on each tile, that is).
- Players take turns. (insert mandatory thematical rule for choosing first player here:) The last person to find mouldy food in their fridge may begin. 
- On your turn, either A) Grow and place a new piece next to one of your existing ones, or B) Spread by moving one of your existing pieces to a new position that is 2 steps away instead of next to your old position.
- Replace all opponent pieces next to the piece you just placed/moved with your own. In other words, you Absorb them into your own mouldy growth. And that completes your turn.
I can add step-by-step photos from one of the test games (Square board with 4 players), and I could also add photos illustrating the moves, if necessary. Let me know - please comment below or contact me in the facebook group - if you think this is necessary!
Game End and Winning Edit
Win option A Edit
Play until the board is full, and count the number of cubes. This might be more suitable for 2-player games or if you prefer to play "to the bitter end" in case of 3 or 4 players.
Win option B EditPlay until one of the players have placed all 20 of their cubes, and they instantly win.
Alternative geometries Edit
As seen above, I've tested this with both an orthogonal board (as in Virus Wars and the mobile app) and a hexagonal board (because I wanted to create a 3-player variant - it is cool that the Green Box tiles allow this - and also since it sets this game more apart from the others).
On a hexagonal board, you will have 6 directions in which to grow (1 step) or spread (2 steps), and on a square board you'll have either 4 or 8 directions. I didn't play with only 4 directions, but I can imagine that it could either be too restrictive or that it would end up being a poor version of Go.
There's no reason not to try out other board geometries like a perfect triangle, a giant plus sign etc, but just like real mould, the more crooks and crannies your board has, the more places you'll end up with pieces that cannot be moved, and this will limit the strategic options.
I actually did set up the perfectly triangular board, but it seemed that players would quickly get entrenched, so I didn't actually play this variant, and instead modified the board to the Quasi-Triangular shape.
Adding 2 cubes in the middle of the side opposing each corner, like in the Quasi-Triangular setup, might reduce these issues somewhat. Or perhaps even better, start with only those 2 cubes in the middle of each side, and have no cubes in the corners to start with. It needs to be tested.
Alternative movement rulesEdit
There are two possible movement rules when Spreading:
Movement option A Edit
You can only spread/move 2 steps in a direct line (like a Queen in chess). This also disallows you from moving around corners like those on the triangular board.
Movement option B Edit
You can spread/move to a position in the "row" with is 2 steps away, but it doesn't have to be in a straight line (like a Queen OR a Knight in chess).
Option B allows you to reach all positions that far away, and there's "nowhere to hide" when approaching an opponent.
I think more playtesting is needed to figure out which board is better, or if both are equally good (i.e. that they don't restrict the choice of strategy). So please try it out and post your feedback here :-)
- ↑ I started with a regular triangle with sides of 7, and then added 2 tiles along the middle of each side. What I got then is actually a 6-armed star of David with 3 truncated corners - I realized afterwards that with 37 tiles total it would be possible to make a complete star of David)
- ↑ I was considering the possibility of a mechanism for variable player order, i.e. a different first player in each turn. However, this might over-complicate the game and also having two moves in a row would probably be too powerful. There might be a reason why I haven't seen any zero luck abstract strategy games with (non-random) variable player order? Or does this combination exist?