The gear scripts are Matlab scripts to create curves for involute gears. These scripts create an x-y path for gears given the diametral pitch series, pitch angle, number of teeth, gear height, and a few other characteristics. My main reference for creating these gears is the Machinery Handbook pg 1995 to 2010, and the McMaster Carr catalog (which has examples for different pitch series).  .
The paths can then be used to create stl files for spur gears.