Kids these days have no idea what "back to the drawing board" actually means: computers do most of the dreary design work nowadays, and most designs never see any ink anymore. I grew up in an age where the drawing board was still an item:
A large slanted table capable of holding a sheet of A0 paper, with a mechanical contraption attached to the top, which kept a combination of two perpendicular rulers neatly horizontally aligned. It had a large round knob so you could draw any angle you needed.
The photo at the top shows an office from the fifties, where numerous people were employed to make the drawings used to create tools and products.