On your computer screen sits an equilateral triangle with three constructed medians. The medians concur in a single point. You click and drag a vertex with the computer mouse. You point at the triangle's vertex and you drag it. The cognitive distance between what is on the screen and the mathematics behind it is minimal.
Motion is continuous .
Change takes place during the drag. The mathematical objects represented on the screen stay coherent and whole at all times. As the triangle's vertex moves from point A to point B, you can see all the intermediate states. The environment is immersive . The interface is minimally intrusive so that your focus is on how to accomplish your mathematical goals, not on how to drive the technology.