False coin test

This is an application to simulate a comparison balance to solve the following problem:

You have 12 coins. One of them is false. You don't know if the false one is heavier or lighter than the others. You have to discover which one is the false coin and if this coin is heavier or ligther than the others.

You have only a comparison balance, so you don't know the exactly weight of the coins. You have to achieve the answer with only three weighings.

This is a hobby.