See also: the distinct shape of the flap and landing gear levers (which are often located next to each other).
replyhttps://aviation.stackexchange.com/questions/22680/why-is-th...
... and yet on more than one occasion, pilots have taken off and prematurely retracted the flaps when they meant to retract the gear!
replyHumans 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