You know what I’m talking about — the strange, bumpy things you see every fall. They’re piled high at all the stores, squatting on front porches, or sitting in a bowl your friend insists is “autumnal.

This is the season when autumnal displays surround us. Decorative gourds seem to appear overnight, as if beamed down from an alien spacecraft: striped, speckled, warted, and winged. Bright bursts of ...