Two Dice from Three Dice
This is a solution to the "three indistinguishable dice problem" posed by Matt Parker at https://youtu.be/xHh0ui5mi_E.
You have three indistinguishable dice which must be rolled together. How do you use them to simulate the result of rolling two dice with the correct probabilities.
Here is the system:
1. Calculate the total of the distinct numbers you see (do nothing if all the same).
2. Subtract 2 from the total.
3. If the total is out of the range of 2-12, add or subtract 7 to put it in range. If you got three of the same, the result is 7.