Add another smooth stone block on the outside of both center pistons. These will act as shelves so we can reach the top pistons with redstone. Place a redstone torch under each of these blocks. When you do, the bottom two pistons will expand, closing the bottom ⅔ of the door. Plac...
The main signal (the redstone torch on the right) has a strength of 14. That's because I used 2 redstone dust, and as we saw in the previous part a redstone signal decays (gets weaker) with every block it needs to pass.