You’ve seen them on Reddit, Facebook, 4chan, and all over the web: those funny image macros with the bold captions. Netizens call them memes, a word co-opted from Richard Dawkins that originally stood for a simple unit of cultural information. Online they’ve come to be known for their viral wittiness and ecstatic geekery.

It comes as no surprise that there are plenty of memes appealing to the maker set. We’ve brought together 21 of them on topics like 3D printing, Raspberry Pi, sewing, and more. Have a look below.