Shader thing is a program that renders simple GLSL fragment shaders.
It supports some of the input variable names from ShaderToy and glslsandbox.com.
iMouse- The mouse location in pixel coordinates
iResolution- The dimensions of the window in pixel coordinates
iTime- Time since the start of the program in seconds
iTimeDelta- Time passed since last frame in seconds
iFrame- Total frame count since the start of the program