# tetrahedron(height:in:restitution:) Creates a regular tetrahedron, a pyramid with four triangular faces, that the player tosses during gameplay. ``` static func tetrahedron(height: Float, in unit: UnitLength = .meters, restitution: Float? = nil) -> TossableRepresentation ``` ## Parameters `height` The height of the tetrahedron. `unit` The unit of measurement for the height. `restitution` The coefficient of restitution, in the range [0, 1]. ## Discussion The vertices for the simulated tetrahedron are oriented with one face downward toward -y with that face’s vertex oriented toward -z. In this orientation, the height (h) is measured from face to opposing vertex, and the vertices have the following coordinates, which all lie on a circumscribed sphere of radius r = h/2 ⋅ 3/2: Apex - { 0, +3/2, 0 } ⋅ h/2 = { 0, +1, 0 } ⋅ r Base0 - { 0, -1/2, -sqrt(2) } ⋅ h/2 = { 0, -1/3, -sqrt(2)⋅2/3 } ⋅ r Base1 - { +sqrt(6)/2, -1/2, +sqrt(2)/2 } ⋅ h/2 = { +sqrt(6)/3, -1/3, +sqrt(2)/3 } ⋅ r Base2 - { -sqrt(6)/2, -1/2, +sqrt(2)/2 } ⋅ h/2 = { -sqrt(6)/3, -1/3, +sqrt(2)/3 } ⋅ r Higher restitution values indicate materials that conserve kinetic energy during collisions, causing objects to bounce off each other elastically. Lower values suggest materials that absorb kinetic energy, resulting in less bounce and more energy loss upon impact. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)