I have some screenshots in the Attachment let you see how to build and work
whit this bug u can use x ray whit out mods
build:
step1: dig 3 wide 1 height down
step2: place 1 sickey piston and infront of the stickey piston a redstone block
step3: near the redstone block 1x1 down place 1 redstone in it and redstone near the piston
step4: place a lever on the where the near redstone block now is and
use:
step1: stand in the middle of the redstone block
step2: double switch the lever
stuff that you need :
1 stickey piston
2 redstone
1 redstone block
1 lever
Duplicate of MC-1769.