> Each knob on the Master Control Panel has a different geometrical shape, allowing the user to distinguish the knobs by feel.

Auto manufacturers should take a clue here.

See also: the distinct shape of the flap and landing gear levers (which are often located next to each other).

	▲	aaronmdjones 36 minutes ago \| parent [-]
		... and yet on more than one occasion, pilots have taken off and prematurely retracted the flaps when they meant to retract the gear! Humans fascinate me sometimes. https://assets.publishing.service.gov.uk/media/578defbae5274... https://assets.publishing.service.gov.uk/media/578def27ed915... (Two separate incidents in the same year, on the same day, even) EDIT: Updated links to point to incident reports