Pendulum Toy; G. Everett, 1967
From all appearances, this looks more like a tool than a mere toy. A very stable and sturdy design, which is an important consideration if you wish to produce nice quality harmonograms. It combines the motion of two pendulums that rotate in a single plane (a Lissajous Figure Drawing Machine). The two pendulums intersect at a bit less than the optimum 90 degree angle.
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