Apr 15, 2014 8:31 AM
Remember pestering your trigonometry teacher about when you would ever need to know that kind of stuff? Well, we bet you never imagined the answer to that question would be, "For telling time." Amazingly, we were able to solve all of the equations on the Mathematical Expressions Clock ($30)...but only because we already know the layout of a clock. That said, anybody who can solve these expressions even without context really ought to hang the clock on her wall to show off her insane smarts.