User blog:UnikarnzMagik/Preservation of 'Logic Idea'

1 . by Ticktatwert - using pressure plate and wires
requirements : 2 hatches and 2 wires depend and 1 pressure plate.

2 . by manga12320 - using laser and laser detector and wires
requirements : 2 hatches and 2 wires and 1 laser and 1 laser detector.