Can someone explain to me how this is happening?

It seems as though I’ve accidentally made a capacitive touch sensor while working on some logic gate stuff in my engineering class. What I don’t get is how I made a capacitive sensor with just logic gates? Note that I’m not touching the wire in this video, my hand’s just getting near it. The wire is not moving. I also don’t expect anyone to deconstruct my super messy wiring, but how could this happen without any timing circuits or anything?