Drawings. They do it for me, perhaps it started off with meccano or lego build-explanations, or even Grandad-fdb drawing propellor designs or gawd knows what before him. On one extreme, there's the expanded engineering drawing of an engine's internals, on the other a Ford brochure from the 80s showing how four adults sit with legroom to spare in an Escrote.
Post what you like, with the emphasis on the third word. Or just post any old shit, who cares? Even I'm a sucker for an pic of a VW Strength-through-Joy wagon, when of this sort. Here are a few more which I enjoy,
If you think it's autoshite room 101, not justed posted at 1.01, then say so.