The most recent releases of JRubyArt and propane feature sketches using the PixelFlow library for processing by Thomas Diewald. Some of the sketches are based on classic ShaderToy Demos, and demonstrate the sort of graphics performance not normally associated with ruby. For JRubyArt you just need to install the PixelFlow and associated libraries (controlP5 and peasycam) from the vanilla processing ide. For propane it is a little more complicated and the libraries require a manual install, and manual updating thereafter (the biggest drawback of this model), potentially this could be avoided by creating gem versions of the libraries as we have for toxiclibs, geomerative and wordcram.