The "unit" abbreviated "U" is the most basic and irreducible unit of three-dimensional measure available to the civilian population of the city planet. The unit is also a component of the full 0-4 dimensional measure system used by the [[core]] and it's many emissaries.
The unit is derived from an advanced type of trigonometry. Unlike with terrestrial mathematics, neotopian trigonometry is not formulated within the context of conventional quadrilateral X Y Z vectors, but rather π (pi) based triangular vectors; more specifically the 60° vertex that constitutes a regular tetrahedron. Fundamentally the purpose of this is to eliminate virtual calculations that do not deal directly with volumetric space. Therefore the unit value is treated as a whole number, it is not reduced due to the fact that two-dimensional space is not physically possible. This is not to say that conventional mathematics is invalid, it is merely a simplification that allows for precise contextual metrics.
The figure above illustrates the basics of unit based trigonometry. Although technically the 2D is not disclosed, and the terrestrial conversions cannot be resolved; I've included them both to provide a little context.
The relative size of a neotoy unit is approximately 59 feet.