This animation is based on the standard Sierpinski triangle.
However, instead of using 1/2 as the contraction factor (the new point
is 1/2 of the way from the current point to one of the corner
points), the factor is varied sinusoidally over the range 1/3 to 2/3.
This gives the difference between the overlapping triangles and the
dusts.
While it appears that the animation is 3D, it is really 2D. The
corner points move around on 3 separate curves, giving the appearance
of twisting and turning in flight.
