Remember, no googling etc, only use your wits.
Day 4
You are standing in an (almost) empty room. There are a few things laying around the room; a small magnet, a hand mirror, a cow clip, some shoelace and a wooden six-inch measuring stick (ruler). There is also a vertical pipe attached to the floor. The pipe is roughly one foot long. Its diameter is small, slightly larger than a ping-pong ball. In fact there is a ping pong ball stuck at the bottom of the pipe. Using only what is currently available, how could you recover the ping-pong ball (without harming its condition)?
I would have put water...but there's none?
So I will use the mirror to look at myself. I'd probably admire myself for a couple minutes. I'd probably use the stick too...you know...just to compare something. Then I'd feel like...well hmm..let's just say I'll use some of my own liquid and pour my liquid onto the pipe to push the ping pong ball out. Pee is probably the best to use..since saliva and my other kinds of liquid may not be enough.