anchor.diff:          //  Add a bit to theta (how much we're rotating the scene) and create the modelview
           //  and normal matrices.
     
  -        theta <- 0.01f
  +        theta <- theta + 0.01f
           scene.CreateModelviewAndNormalMatrix(theta)
               
           //  Clear the color and depth buffer.
  
positive.code: module TrefoilKnot = 
      open SharpGL.SceneGraph.Shaders
      open System.Collections.Generic
      //open SharpGL.Shaders
      open SharpGL.Enumerations
  
      //  Original Source: http://prideout.net/blog/?p=22
  
negative.code:         /// Initialises the Scene.
          /// </summary>
          /// <param name="gl">The OpenGL instance.</param>
          member x.Initialise(gl : OpenGL) =
          
              //  We're going to specify the attribute locations for the position and normal, 
              //  so that we can force both shaders to explicitly have the same locations.
  
  
              //  Create the per pixel shader.
              do shaderPerPixel.Create(gl, 
                                       ManifestResourceLoader.LoadTextFile(@"CelShadingExample\Shaders\PerPixel.vert"), 
                                       ManifestResourceLoader.LoadTextFile(@"CelShadingExample\Shaders\PerPixel.frag"), 
                                       attributeLocations)
              
              // Create the toon shader.
              do shaderToon.Create(gl,
                                   ManifestResourceLoader.LoadTextFile(@"CelShadingExample\Shaders\Toon.vert"),
                                   ManifestResourceLoader.LoadTextFile(@"CelShadingExample\Shaders\Toon.frag"), 
                                   attributeLocations)
              
              //  Generate the geometry and it's buffers.
              do GenerateGeometry(gl, positionAttribute, normalAttribute)
  