Found this on MLIA
Yesterday, I wrote Time Machine on the shower door of my dorm suite. I included a secret panel with numbers and symbols. Today, I walked in on one of my suite mates punching in an imaginary code before showering. We have all agreed that showering has become extremely adventurous. MLIA

All i can think is what if it did work and you turned up in some random time, but naked? Talk about embarrasing

lolz