For those who are playing along at home: the 4017 is a widely used chip that switches one of ten outputs high when a pulse is received on the 'clock'-pin. It's frequently used as a counter to make LEDs light up in sequence, in timers and that sort of thing.
The 4017 is housed in a 16-pin chip (which means 8 pins on each side). Wouldn't it be convenient if the sequential outputs were located on sequential pins?
But of course, that is not the case. Output 0 is on pin 3, output 1 is on pin 2, output 2 is on pin 4, output 3 is on pin 7 -- while output 5 is on pin 1 and output 7 is on pin 6.
Why!? Why is everyone forced to make multi-layer PCB layouts just to accomodate the weird design of this chip? Why didn't anyone come up with a design that does put the leads sequentially? Who thought up this unholy contraption? Why are we forced to put up with it?
Needless to say, I would gladly kick the responsible persons in the nuts, on behalf of every electronics hobbyist on the planet.