The Negative Pedal Curve (NPC) of the Ellipse with respect to a boundary point M is a 3-cusp closed-curve which is the affine image of the Steiner Deltoid. Over all M the family has invariant area and displays an array of interesting properties.

中文翻译：

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斯坦纳帽：与椭圆相关的等面积三角肌

椭圆相对于边界点 M 的负踏板曲线 (NPC) 是 3 尖点闭合曲线，它是 Steiner 三角肌的仿射图像。在所有 M 中，该族具有不变的面积并显示出一系列有趣的特性。