redstone torches activate pistons with air.

I was making a redstone machine with pistons and torches and noticed that pistons were activated by a redstone torch that wasn't next to any pistons or any blocks or other redstone to power the piston.
simply place a solid block 2 blocks above the ground, then place a redstone torch on the side of the block, then place a piston on the ground under the redstone torch with 1 block of air spaced between them, the piston should activate.