This demo employs a 3D interface that displays a parameterized 3D curve. Up/Down Right/Left arrows and a/z keys rotate the curve along the x,y,z axis.
The 3D interface is a based on a projection algorithm I developed some years ago to make Geometer's Sketchpad display 3D curves. I learned much about curve animation in Scratch from @leszpio who has some fantastic animations in his site. This work is a variation of one of his animations. I also learned a tremendous amount from @Mr_Pyro_ 3D Wireframe Engine project about optimizing rendering and keyboard effects. Much much thanks.