It started with a tiny 1/72 shape made from the wingroots and engines of WWII plane with a spoon on top. I kept it around, meaning to eventually build it into a ship. Dog decided it was a superfluous and chomped it. I STILL couldn't throw it away so I thought fine, I'll finally use it for something. I further decided that it would be a pretty outlandish design, enhanced by equally colorful paint.
Added layers of wings just to give it bulk in two dimensions, then outlandishly huge engines, and sleekness-destroying outboard tanks. Could be a nimble little fighter, but no, let's make it a tug. Or, better, a lowly tractor-trailer!
The anti-sleekness continued with a pretty ugly 1/35 German trailer hitch. Fitting it with quarter-inch plastic stock made it the almost perfect fit with an old HO-scale freight car.