I've always been a fan of metaphorical descriptions of ineptitude or slack mental function.
"Dumber than a [name your container] of hammers" is a keeper. Its cousin, "Dumber than a box of rocks," is also good, especially when said with a bad imitation of a South Bawrstin accent.
But I'd never encountered photographic proof. The proverbial sack or bag or box remained as elusive, visually, as any UFO.
Until Saturday, during the townwide yard sale (tag sale/garage sale - ain't our language wonderful with its plethora of terms for things?)
At last: proof, and I coin my own variant:
Dumber'n a bucket o'hammers with a coupla saws thrown in.