

Better than ringing a stupid bell and yelling “Outta my way, butthead,” Trotify dignifies the alert. Downloadable plans are available for free here; 3D printable files ($4.57) here.
[Found here a few years back.]


Looks like a 1987 Toyota Celica 2005 Honda Accord [?] retrofit courtesy of Honda. If he did it right, it’ll run forever, but it needs a plywood spoiler. And, nope, the double yellow doesn’t mean a damn thing.
[Found here.]
Okay 1502 AD is technically the 16th Century, but the engineering was already in existence.

VERY cool – You can build it on the spot if there’s available timber, no connectors required, and you can knock it down and take it with you once your army has crossed the stream, arroyo, ravine or ditch. Here’s one in use (with planks installed):

This kid constructed one without notches or connectors, using friction and compression only.
[Top image from Da Vinci. 2nd image from here, video from here, links found in here.]