NOR gate in redstone

Two inputs power a single block. A torch on its side is off if either input is on. Footprint 3 wide × 5 deep × 2 tall. Build it block by block in Minecraft.

How to build it

NOR is the natural shape of a redstone torch attached to a block that has multiple inputs. The torch turns off as soon as any input powers the block.

1. Place a solid block in the middle of the layout.
2. Run dust from input A into the side of that block.
3. Run dust from input B into another side of the same block.
4. Attach a redstone torch to any remaining side of the block.
5. Run dust from the torch out to the output Y.

Why it works

A redstone torch on a block is "off" if the block is powered. Power the block from A or B or both, and the torch extinguishes. The only time the output is high is when neither input is high — which is exactly NOR: ¬(A ∨ B).

Gotchas

• The block can only accept input from three sides if you want the torch on the fourth — plan the layout before placing blocks.
• Because redstone torches cannot be placed on all block types (glass, slabs, stairs), stick to full opaque blocks like stone, cobblestone, or wool.

It's also a NOT gate

With one input, NOR is just a NOT. That's why a single-torch-on-block is the building block of almost every redstone circuit.