After a few hours of messing around and watching a picture of the double piston extender by NorthWindStudios I managed to make MY FIRST 3x3 Piston door!! I'm so happy right now!!
3x3 Piston Door Mechanics | Double piston extender - YouTube
How can I get the bottom middle block into place? I already have a double piston extender for the center block. : r/technicalminecraft
How to create a very compact 2x2 double piston extender door with all redstone contained beneath floor level : r/Minecraft
The Worlds SMALLEST Double Piston Extenders (Minecraft 1.13+) - YouTube
How to Build a SIMPLE Vertical Double Piston Extender - YouTube
After a few hours of messing around and watching a picture of the double piston extender by NorthWindStudios I managed to make MY FIRST 3x3 Piston door!! I'm so happy right now!!