heres a simple and gate and a simple or gate and a simple nor gate.

AND GATE- make a big hollow rectangle of antimatter and put two peices of dissolve material near the middle. Make a ball with a magnetic witch on it on top the tallest one. Make a magnetic key at the bottom. attach your switched to the dissolve and when both of them disolve then your ball hits the bottom and DING DING DING the magnetic key goes off.

Or gate- again make a rectangle with same material but this time put a long pole of ati matter down the center and disolve on both sides. You now have too very close rectangles like the and gate but with only one disolve material. attach both switches to either disolve and when the ball falls on either it will activate the same switch.

Nor switch- do i really need to explain DONT HOOK YOUR SWITCH TO ANYTHING