There were a couple of unbreakable rules in design & tech classes. One of them was to always wear safety glasses. Another was to never, under any circumstance stand behind a table saw while it’s operating. Why?
While performing a cut, Ken Spitulski from KenCraft lost control of a huge board. It sailed 20 feet across his workshop and embedded itself 8 inches into a wall before hitting (and badly denting) the exterior steel siding. If anyone had been stupid enough to walk by, they’d have been worse for wear, to say the least.
For his part, Ken decided to leave it stuck there as a reminder.