Most people have no idea how their car works. That was even truer in the 1930s, when the Hohm Company of Germany started making miniaturized models to educate potential buyers on which pedal made the car go. Pistons pumped, driveshafts spun, clutches depressed, gears shifted, and a lust for horsepower was stoked. These days, a mint Hohm, like the one the antique hunters at Aspen’s Georgia Brown unearthed last year, costs as much as a brand-new Chevy Spark. And it doesn’t depreciate as soon as you take it off the lot.