Good teaching tool
It’s a good simulator to study wave interference without an actual ripple tank. My suggestions to improve it further would be to 1) allow the user to move and nudge the point sources with the keyboard arrows and perhaps provide the option to snap them to a hidden grid for precise positioning of the sources, 2) provide explanations and notes or links to online sources about the different setups for study, such as what is a phased array or a coupled cavity, 3) allow the user to export a recording as a Quicktime movie besides the current default avi file, and 4) give the user the option to change the dimensions of the tank besides the current, fixed 600 x 600 pixel square.
Jettamesis about Ripple Tank