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Package demo2 (in demo2.i) -

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DOCUMENT demo2 Exhibit quadrilateral mesh plots in 3 movies of a drumhead. The drumhead is initially stationary, but has a bump near one edge. Yorick is solving a 2D wave equation to compute the evolution of this bump. The first movie is a filled mesh plot with color "proportional" to the height of the surface of the drum. A few well chosen contour levels (here 3) add a lot to a filled mesh plot. The second movie is a "3D" perspective plot of the height of the drumhead. In this movie, the mesh lines are drawn, which is slightly confusing since the cells are not all the same shape. The second movie is a "3D" shaded plot of the height of the drumhead. Yorick computes surface shading based on the angle of each cell from a light source. As you watch this, you might reflect on the two dimensionality of your retina. What Yorick lacks by way of 3D graphics is really just fancy hidden surface algorithms; the simple painter's algorithm used here and in plwf.i is easy to implement. There are two optional arguments to demo2: the first is the number fo the movie (1, 2, or 3) you want to watch; the second is a time limit on the duration of each movie in seconds (default is 60 seconds each).