Building unit

Claim 1

A ten faced polyhedral building unit adapted to interfit with like units in a building system characterized in that it has: a. two rectangular faces of like size in opposed parallel relation each having relatively parallel side and end edges; b. four isosceles trapezoid end faces of like size arranged in pairs at opposite ends of said unit with the major parallel edges of each pair of end faces coterminous with adjacent end edges of the rectangular faces, the trapezoidal end faces of each pair converging in a direction outwardly of the unit and having the minor parallel edges of each pair of end faces coterminous with each other; c. four isosceles trapezoid side faces of like size arranged in pairs at opposite sides of the unit with the minor parallel edges of each pair coterminous with adjacent side edges of the rectangular faces, the trapezoidal side faces of each pair converging in a direction inwardly of the unit and having the major parallel edges of each pair of side faces coterminous with each other; d. the spacing between the major and minor parallel edges of each of said isosceles trapezoid end faces being equal to the spacing between the major and minor parallel edges of each of said isosceles trapezoid side faces and the interior angle between each pair of trapezoidal end faces being 120* and equal to the angle between each pair of trapezoidal side faces measured exteriorly of the unit, said minor parallel edges of the side faces having a length less than two times the spacing between the major and minor parallel edges of the end faces, and said rectangular faces being square whereby the major parallel edges of the end faces have a length equal to the minor parallel edges of the side faces.