Hey all! I wanted to share this for a while now, but the update detector was even worse before 1.7.4. So now I'm finally uploading this design to prank your friends even more or if you just want a very clean way to defend your mining base. Hope all of you like it and I'll see you next week!

NOTE: In the video I used a normal piston for the second design. This isn't needed anymore! I had this design in a world for a while now and didn't thought of it that the piston isn't needed anymore! Sorry for the mistake!