ALT A meme following the "They have played us for absolute fools" format. It reads: " STOP DOING AUTODIFF COMPUTER PROGRAMS WERE NOT TO BE DIFFERENTIATED! HUNDREDS OF AD SYSTEMS and yet NO REAL-WORLD USE FOUND for anything more than applying the CHAINRULE on derivative functions written BY HAND. Want to differentiate arbitary functions anyway for a laugh? We had a tool for that it was called FINITE DIFFERENCING! "The pullback is product of the jacobian transpose with the sensitivity" — statements dreamed up by the utterly deranged. (This is REAL AD, used in REAL AD systems) " Then are shown two pictures. A category theory optic diagram labelled "?BINOCULARS?". and a line-graph showing subderivatives labelled "LINEY-BOY" The text then concludes: " `gradient(x->println("$x apples"), 3)` They have played us for absolute fools "