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In page Duocylinder:

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In 3-space, a cylinder can be considered intermediate between a cube and a sphere. In 4-space there are three intermediate forms between the tesseract (1-ball × 1-ball × 1-ball × 1-ball) and the hypersphere (4-ball). They are:

  • the cubinder[citation needed] (2-ball × 1-ball × 1-ball), whose surface consists of four cylindrical cells and one square torus.
  • the spherinder (3-ball × 1-ball), whose surface consists of three cells—two spheres, and the region in between.