Other things that are non-self-evident except to people already familiar with APL: * means exponentiation, not multiplication; and "⍟var which is Pi times var"

Other things that are non-self-evident except to people already familiar with APL: * means exponentiation, not multiplication; and "⍟var which is Pi times var" is incorrect: it's actually log(var). I have to confess that I don't find this sort of example very compelling; Box-Muller isn't much more than a one-liner in any language. I mean, here it is in C, not noted for its richly expressive terseness: double norm(void) { while (1) { double u=rand01(), v=rand01(); double s = u*u+v*v; if (0 < s && s <= 1) return u * sqrt(-2*log(s)/s); } } (I assumed that we already had a rand01() function equivalent to your "u"; I suggest that in any nontrivial program the gain in brevity from the single-character name is outweighed by being unable to call a local variable "u" and, if you have a bunch of these, the cognitive load of remembering what all the single-character names mean.) I bet the C implementation is distinctly easier to make sense of for most mathematicians and most programmers, and it's not even substantially longer. (APL: 94 non-blank characters. C: 111 non-blank characters. I remark that counting non-blank characters is about as favourable a metric for APL as one can reasonably ask for.) One can code-golf it further: combine the declaration of u,v with that of s (saves 5 non-blank characters --> 106); switch to your "u" instead of my "rand01" and rename u,v to (say) x,y (saves 10 characters --> 96); convert to do/while and use commas instead of {;;;} for body (saves 4 characters -> 92). That looks like this, and I think is still pretty easy to read: double norm(void) { double x,y,s; do x=u(), y=u(), s=x*x+y*y; while (s==0 || s>1); return x*sqrt(-2*log(s)/s); } (Note: character-counting is by hand and it's entirely possible I'm out by a couple of chars either way.) [EDITED to fix formatting screwage; aargh, I hate HN's treatment of asterisks]