It uses HTML5 Canvas 2D (Vector Graphics) and random generator.
Click 'Next Kaleidoscope' menu item below or Refresh button on Browser to generate next picture.
Click 'Mouse Right Button/Save Image As...' in the field of interesting image.
You cannot get it next time.
Or press [Print Screen] Key to fix and 'Save As' some image.
Use the Kaleidoscope Image as idea for your own Stained Glass Window.