This is the iconic image of David Rowland's famous 40/4 chair, taken straight from his 1963 patent (US 3,080,194).
Forty of 'em, stacked in 4' of vertical distance. A simple and elegant solution to a problem.
Next time you sit in a lecture hall, library, or any other large space with lots of chairs, look closely at the chairs. Chances are they are based to some extent on Mr. Rowlands's invention... and the expired patent.