Lemniscatoids

Four-bar crossed-crank linkage for drawing Lemniscatoids

1) AB = CD = a
2) AD = BC = 2b
B rotates around A. The middle of BC describes a lemniscatoid with equation (From Artobolevski bd I, p. 522).

(x^2 + y^2)^2 = a^2(x^2 - y^2) - 4b^2y^2

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