At Xerox PARC in the 1970s, most people kept a can of copier
cleaner (isopropyl alcohol) at their desks. When the steel ball on
the mouse had picked up enough {cruft} to be unreliable, the
mouse was doused in cleaner, which restored it for a while.
However, this operation left a fine residue that accelerated the
accumulation of cruft, so the dousings became more and more
frequent. Finally, the mouse was declared `alcoholic' and sent
to the clinic to be dried out in a CFC ultrasonic bath.

:Duff's device: /n./ The most dramatic use yet seen of {fall
through} in C, invented by Tom Duff when he was at Lucasfilm.
Trying to {bum} all the instructions he could out of an inner
loop that copied data serially onto an output port, he decided to
unroll it. He then realized that the unrolled version could be
implemented by *interlacing* the structures of a switch and a
loop:

register n = (count + 7) / 8; /* count > 0 assumed */

switch (count % 8)
{
case 0: do { *to = *from++;
case 7: *to = *from++;
case 6: *to = *from++;
case 5: *to = *from++;
case 4: *to = *from++;
case 3: *to = *from++;
case 2: *to = *from++;
case 1: *to = *from++;
} while (--n > 0);