Downward Double Piston Extender, it works but I don't understand why. Any explanation? - Redstone Discussion and Mechanisms - Minecraft: Java Edition - Minecraft Forum - Minecraft Forum
Same double piston extender, different outcome. - Redstone, Commands and Mechanisms - Minecraft - Minecraft Forum - Minecraft Forum
The Worlds SMALLEST Double Piston Extenders (Minecraft 1.13+) - YouTube