I notice that when generating several plots, they are cascaded upon
one another, one slightly to the right and below of the previous one.
However, when the plots get near the bottom of the screen, they keep
cascading even when only the top of the plot can be seen. Should the
cascading not reset when the *bottom* of a frame touches the bottom of
the screen, and not the top?
Also, when the previous plot disappears prior to the current plot, is
there any need to cascade them at all? Currently, the plots cascade
even when prior plots have disappeared.