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===Sweeping a line segment=== {{CSS image crop |Image = Mobius strip.gif |bSize = 400 |cWidth = 185 |cHeight = 150 |oTop = 115 |oLeft = 105 |Description=A Möbius strip swept out by a rotating line segment in a rotating plane}} {{CSS image crop |Image=Plucker's conoid (n=2).gif |bSize=360 |cWidth=240 |cHeight=240 |oTop=60 |oLeft=60 |Description=[[Plücker's conoid]] swept out by a different motion of a line segment}} One way to embed the Möbius strip in three-dimensional Euclidean space is to sweep it out by a line segment rotating in a plane, which in turn rotates around one of its {{nowrap|lines.{{r|maschke}}}} For the swept surface to meet up with itself after a half-twist, the line segment should rotate around its center at half the angular velocity of the plane's rotation. This can be described as a [[parametric surface]] defined by equations for the [[Cartesian coordinates]] of its points, <math display=block> \begin{align} x(u,v)&= \left(1+\frac{v}{2} \cos \frac{u}{2}\right)\cos u\\ y(u,v)&= \left(1+\frac{v}{2} \cos\frac{u}{2}\right)\sin u\\ z(u,v)&= \frac{v}{2}\sin \frac{u}{2}\\ \end{align}</math> for <math>0 \le u< 2\pi</math> and {{nowrap|<math>-1 \le v\le 1</math>,}} where one parameter <math>u</math> describes the rotation angle of the plane around its central axis and the other parameter {{nowrap|<math>v</math>}} describes the position of a point along the rotating line segment. This produces a Möbius strip of width 1, whose center circle has radius 1, lies in the <math>xy</math>-plane and is centered at {{nowrap|<math>(0, 0, 0)</math>.{{r|parameterization}}}} The same method can produce Möbius strips with any odd number of half-twists, by rotating the segment more quickly in its plane. The rotating segment sweeps out a circular disk in the plane that it rotates within, and the Möbius strip that it generates forms a slice through the [[solid torus]] swept out by this disk. Because of the one-sidedness of this slice, the sliced torus remains {{nowrap|connected.{{r|split-tori}}}} A line or line segment swept in a different motion, rotating in a horizontal plane around the origin as it moves up and down, forms [[Plücker's conoid]] or cylindroid, an algebraic [[ruled surface]] in the form of a self-crossing Möbius {{nowrap|strip.{{r|francis}}}} It has applications in the design of {{nowrap|[[gear]]s.{{r|dooner-seirig}}}}
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