A wire is a basic component of circuits and conducts power.
A redstone wire is formed when someone right clicks on a solid block while redstone dust is selected in the inventory. Every adjacent wire will connect, even if it's 1 block higher or lower, unless when blocked by a solid block.
A wire can be infinitely long, but the power will only last for 15 blocks. A wire has no delay when conducting power.
Every wire has memory flag for each direction, to remember where it is connected to. When a redstone wire is placed, it checks the block north, east, south and west for redstone components, that same set of blocks is checked 1 block higher, and it's checked one block lower. So a torch on top of a block would 'pull' the wire towards it and activate that flag. Wires, torches and every input source. Repeaters won't 'pull' wires. An input source from above or below won't affect the flags.
In right image, block A would only become powered if one of these apply:
- None of the directions are connected.
- If C is connected and both B and D aren't.
To power a block using a redstone wire, the connection to the block itself won't matter for the result.
- If there is a torch on top of C, and the wire becomes powered, then A will become powered.
- If there is a torch on top of A, and the wire becomes powered, nothing will happen. The wire will point to the block as a straight wire, but C isn't connected, to it won't transmit power.
- If the wire is being powered by a repeater from D. Both blocks A and C will become powered, as none of the directions are connected, because the repeater doesn't connect. If C must not be powered, placing any redstone component on top of C will prevent C from being powered, but allows A to be powered.