Ur Dice

This app is a dice roller for The Royal Game of Ur. Ur uses four two-sided dice that can each roll a 0 or a 1. This gives you a result between 0 and 4 with a unique probability distribution. It's easy to draw an Ur board, and to find small objects you can use as game pieces, but since 0-1 dice aren't common, this makes playing tricky. Flipping a coin 4 times takes too long. You can use any normal polyhedral dice and use odds as 0 and evens as 1, but this makes it hard to tell what you rolled at a glance. You could take 4 normal 6-sixed dice and color 3 of the faces on each with a sharpie, but... actually, you should probably just do that.

But if you don't want to do that, this app is the solution. Launch in fullscreen and place the phone on the table between the two players. Each player has a button to press which will clear the screen and roll four dice with an easy-to-distinguish display.