Andrew was playing with a drinking straw - the kind that has an elbow built in. He put a second kink in it himself and started stabbing it down into the floor and making growly "vroom" noises. I said, "What do you have there? Is that a straw?" He told me it was an excavator. (Actually, he said "dirt," which is what he calls excavators, in addition to actual dirt.)
Then not 10 minutes later, he told me the toothbrush case was a car and proceeded to drive it around the kitchen saying "vroom."
Didn't realize 20 month olds got that abstractly imaginative!