this is a plan9 program.
a frog can jump up to one foot in any direction. what is the probability after N jumps that the frog is within one foot of its starting point?
so here are these three naive C programs:
frog.c - a frog simulator
acc.c - an accumulator that checks the landing position of the frog
change.c - stops when the accumulator is not changing any more
and a shell script:
frog.sh - to run all this crap for weeks and weeks
some results can be found in frog.dat if one does not wish to bog down one's computer. there are, of course, better ways to do this...