These ebay ads for this snail-shaped ruling pen dotted-line drawer are hilarious. Clearly ai-generated by a model that has absolutely no idea how they're supposed to be used. I'm debating buying one anyway, because I've never seen these available for purchase outside of wildly expensive vintage technical drawing sets. I did buy a vintage one, actually, so I can compare the original with the modern reproduction. https://www.ebay.co.uk/itm/336754049742 https://www.ebay.co.uk/itm/236989437625