Junction Box

You run out of wire colors fast on any real circuit. A junction box lets two runs of the same color pass over each other without joining up, so you stop routing long detours around your own wiring or burning a whole color just to get one line past another.

Hit it with a hammer to rotate which way each line enters and exits. That is the entire interface, and getting the orientation you want takes a couple of taps, so place it before you commit to a long wire run. It also sits in midair with nothing behind it, which is handy for suspended logic and a lot easier to get hold of than an Ice Rod.

Buying boxes is much cheaper than buying the full set of colored wrenches. If money is the constraint early in a wiring project, get the boxes first and pick up extra wrench colors once you are richer.