Using SETUP, you can specify the frequency (F)
and the phase (P) of all four pendulums in a
harmonograph.

The parametric equations you are adjusting are:

     -rt
X = e   [sin(F t + P ) + sin(F t + P )]
              1     1         2     2
     -rt
Y = e   [sin(F t + P ) + sin(F t + P )]
              3     3         4     4

where:  r = damping factor, t = time
        F = frequency,      P = phase angle

The four pendulums in a real harmonograph con-
trol the X and Y motions of the paper and pen.
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