Here is an example of a programmer who was able to produce a much more efficient and reliable C program by applying principles he learned in a Scheme course:<p><a href="http://www.cs.indiana.edu/~jsobel/c455-c511.updated.txt" rel="nofollow">http://www.cs.indiana.edu/~jsobel/c455-c511.updated.txt</a><p>Now, this may not be exactly what you're looking for, in that the C code he ended up with is not what you would call idiomatic C, so whether it made him a better C programmer <i>per se</i> is debatable.  But doubtlessly few of his classmates were writing idiomatic C either, and his program's performance and reliability would not have been possible if he hadn't worked through the problem in Scheme first.<p>(Edit: The closing paragraph, in particular, illustrates the  broadly applicable "profound enlightenment experience" that Eric Raymond describes.)