The RZF

Euler's Identity (1737):

Riemann Zeta Function (1859):

source: Gérard Villemin

             Wikipedia

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The Tchebychev Linkage 👩

By Van helsing - self-made largely based on "How to draw a straight line, by A.B. Kempe, B.A.", [1] and [2], CC BY 2.5, Link