euphemistic writes "An Austrian man who became the first person outside the US to wear thought-powered 'bionic' arms has died from injuries sustained in a car crash ... Kandlbauer, who would have turned 23 next month, sustained severe head injuries when the specially modified car he was driving swerved off the road in the south east of Austria and crashed into a tree on October 19. The cause of the accident is not yet known, particularly whether the neurally-controlled arm-prostheses he had been fitted with might have played a role."
We warn the reader in advance that the proof presented here depends on a
clever but highly unmotivated trick.
-- Howard Anton, "Elementary Linear Algebra"