French Curve -- from Wolfram MathWorld

French curves are plastic (or wooden) templates having an edge composed of several different curves. French curves are used in drafting (or were before computer-aided design) to draw smooth curves of almost any desired curvature in mechanical drawings. Several typical French curves are illustrated above. While an undergraduate at MIT, Feynman (1997, p. 23) used a French curve to illustrate the fallacy of learning without understanding. When he pointed out to his colleagues in a mechanical

National Museum of American History

Curve Stitching

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Trefoil Curve -- from Wolfram MathWorld

Curve -- from Wolfram MathWorld

French Curve -- from Wolfram MathWorld

Mill Curve -- from Wolfram MathWorld

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How to Use French Curves - Synonym

RiemannTensor Wolfram Function Repository

Bézier Curve -- from Wolfram MathWorld