I'm looking for a circuit with as input for buttons and as output four pistons (each button stands for 1 piston). If you press a button, the corresponding piston should go off, and the others on, forever. Only if I press another button, i.e. number 2, piston 2 should go off, and 1 should go on again (3 and 4 still "on").
I really don't know how to realize this. Any ideas?