20/20 to Diopter; FFT's; WATOR; Code Search

20/Something vs Diopters
A google answers answer on the conversion between doipters and 20/Whatever vision measurements.

Benchmarked FFT Implementations
Speed comparisons of lots of Fourier transform packages on lots of different platforms.

WATOR Predator-Prey Simulation
WATOR was interesting to watch back in the 80's when computers were so slow. Now, with multi-GHz PCs, it looks a combustion simulation.

Koders Source Code Search Engine
One example: here's a search for finding C++ Fourier transform implementations with a GPL license.