Sometimes, when I'm proctoring an exam, I end up with a little too much time on my hands. So I play with stuff—whatever I've got on hand. In this case, it was one of those clicky pens. It had stopped ...

[u407]’s 3D printed Signspinner was created as a clean/dirty indicator for a dishwasher, and at its heart is a mechanism that works a lot like that of a retractable ballpoint pen. Every click of the ...