Number Line Integers
"Number Line Integers" is an educational simulation in HTML5, by PhET Interactive Simulations at the University of Colorado Boulder.
This simulation is under development and has not been published.
Documentation
The PhET Development Overview is the most complete guide to PhET Simulation Development. This guide includes how to obtain simulation code and its dependencies, notes about architecture & design, how to test and build the sims, as well as other important information.
License
See the LICENSE