A motion sensor connected to a dimmer, which is in turn connected to a light strip, and another wire that runs parallel with a light strip up the wall of a stairwell. It's is a bit of a rats nest of wires as the electronics are not in an enclosure.
The top of a stairwell with a motion sensor connected to a wire that goes down the wall of the stairwell with a light strip above that wire.
I have a stairway without windows, so it's always dark. (And due to my keratoconus I don't see well in the dark) So I made a parallel circuit connected to motion sensors to light up a light strip. (I specifically avoided IoT items) I still have to 3d print an enclosure.2/2