Dave Stanton wrote:
Or when you've designed and etched a printed circuit board with the IC
pins the wrong way round, so that you have to bend all the pins the
other way up.

Or years ago, built a ZX81 on the wrong side of the pcb !!

Dave

Actually the thing that gets me is the recursive installation problem.

I need to install the tiles to put in the basin to establish the vanity
unit height in order to be able to accurately cut the piece of MDF that
sits behind the basin covering the pipes and which has to go in before
the tiles are laid...