A person who learns by doing things wrong - even though they've been told both what not to do AND how to do it right !
Coach: "Whatever you do, slow down before you hit the wall, otherwise you won't make the turn !"
Nurkle: (hits wall after continuing at same speed) "Ouch !"
Coach: "You nurkle ! Try again, but slow down before you hit the wall this time !"
Nurkle: (hits wall again) "Ouuuuch !"
Coach: "You NURKLE !!!"
Nurkle: (makes the turn having slowed down & has look of realisation on face) "Aaaah ! Now I get it !"
Coach: "Nurkle !"