Usually, when a switch is closed the resistance will decrease because a short has been introduced. In circuits with active components such as transistors this is often not the case, but this circuit only contains ordinary diodes, no transistors. As such, it is reasonable to expect the resistance to decrease when a switch is closed. But the opposite is what happens in this case.
This circuit was inspired by a youtube video from Steve Mould: https://www.youtube.com/watch?v=Cg73j3QYRJc
