Drakkarts redstone lab : Minecraft: 3×3 spiral piston door explained, a redstone tutorial

n this redstone tutorial i explain how to build a 3×3 spiral piston door.
It turned out to be pretty compact 3x7x9 and i’ll explain the entire redstone wiring hopefully for everybody to understand how it works.
Worldfile download: bit.ly/1dR3pKw
Music used: “Dance of the Pixies” by Machinimasound.com
Licensed under Creative Commons CC-BY 3.0 Unported License | machinimasound.com/license