Exploring 3D surfaces is a fun way to learn about geometry, physical phenomena or even terrain modeling. Parametric surfaces are surfaces that also change their shape with an extra variable: time. Explore 3D surfaces by using drag and drop and the mouse wheel to zoom in/out. You can enable the t parameter (by clicking on the checkbox) and hit play to see it move. There are three predefined surfaces for you to explore or modify.
Click here to access the example. You will need a WebGL capable browser (and machine).