Little do they know, tunnels are much more effective when they are a) underground and b) not transparent. Good first attempt, kitties, but better luck next time.
Submitter ariled says their kitchen scale's button cell ran out of power and they didn't have another one. Luckily they had two AA batteries, some wire, and duct tape.
Now if I could just train my helper monkey to use a lighter... ~Not-So-Handy Andy