This is my take on a board for Cult of the Lamb's Knucklebones dice minigame. Travel sized and folds in half for easy transport! With optional recesses for magnets and a printed sleeve to prevent your dice from getting lost in your bag.

Made for 12mm dice. You will need 17 of them to ensure the game can always be played to completion.

I got the idea from Maker's Muse, who made a video about designing his own version of this board. I couldn't use his because I can't get 10mm dice locally and didn't want to wait ages for an aliexpress order. So I made my own! (with a better hinge design, if I do say so myself)

Print instructions

• The board should be printed laying flat, the case standing up with the finger cutouts at the top. 
• 15% infill seems to be the minimum for the board. I tried one with 10% and that had some collapsed top surfaces
• None of the files need supports to print
• The case may need a brim, depending on your bed adhesion.

Important: Do not scale these models! The tolerances will also scale and the moving parts become way too loose or tight, depending on how you scale (I learned this the hard way). If you want a board for a different dice size you'll have to look elsewhere I'm afraid.

I've included a version of the files with looser tolerances for printers that struggle with dimensional accuracy. Most printers should be able to handle the regular version (I think, don't quote me on that). If the hinge feels a bit crunchy fresh off the printer, that's normal. It'll wear in with use and become smoother.

There's also board versions with and without holes to glue in 6mm x 1.5mm round magnets. 
If you have different sized/shaped magnets you could change the cutouts e.g. using PrusaSlicer's “Add Shape” feature, or copy the Onshape document into your account and change it there. The magnets that I have are just about strong enough to hold the board closed in my bag, I wouldn't recommend smaller ones.

I've intentionally left the board and case blank on the outside so people can deboss some text into it in a slicer, or if you're a fan of Dymo labels like me stick one of those on.

Game Rules

If you're not familiar with the game's rules here they are (edited slightly from the Cult of the Lamb wiki):

• This is a 2 player game.
• Each player owns one of the two 3x3 grids of dice slots.
• The players take turns. On a player's turn, they roll a 6-sided die, and must place it in a slot on their side of the board.
• Each player's score is the sum of all the dice values on their side.
• If a player places multiple dice of the same value in the same column, the score for those dice is multiplied by the number of matching dice. 
  E.g. if a column contains 4-1-4, then the score for that column is 4x2 + 1x1 + 4x2 = 17.
• When a player places a die, any dice of the same value in the same column on the opponent's side get removed (added back into the dice pool).
• The game ends when either player completely fills up their 3x3 board. The player with the higher score wins.