I found out why people are weirdly obsessed with these pens — and they’re nearly 30% off

You wouldn’t necessarily think that pens are something people would be passionate about, but any daily pen user will tell you ...
Hackaday

retractable pen

[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 ...