Use a pen to write on a piece of paper and explain how a flushing toilet works. Take as long as you like, use as many words and pictures as needed. Once done, realize how bad that explanation is and how little you really know about that topic. Not mine - but source lost. LATER : M... john.philpin.com

@muncman oh now .. I knew somebody from this awesome community would have an angle - will update later - thankyou.