Step 2

The two pistons on the left will push a block outwards and potentially knock a player off the ledge when activated regularly by the pressure plate or any trigger. This will require a normal redstone connection like the one used in the arrow trap.

The two pistons on the right are powered by a NOT gate and will retract in the hopes of making the player fall when they receive power. The torch powering the pistons attached to the floor will turn off when a signal is recieved.