Between the ever changing plain of earth on which the house finds itself and the predictable and filterable light of the sky there exists a Reciprocity of Horizon. The house, a moment between two systems, a co variant derivative between light and ground. Within natural systems there is a play, an essential exchange between energy, it is consumed in order that it may further consume, it is stored only to be later expelled, and it is emitted back into a ubiquitous system that it may be retained at a later time. Its use is multifaceted, yet its essence is the same. The Horizon house provides a rhythm, structure, to which the systems are measured against. They dance across each other in units whose reactions are minuscule accumulate pressure and through its expulsion enable space. Their intricate differentiations of the single unit cross generate identifying relationships which establish their function. These relationships form a language and by growth and incursion into the space between, generate a program in the horizon.. This emergent space in turn demands new dialog between the passing systems, this Reciprocity breeds reactions back into the system which form identity unique to the house, the collective, no longer storing and mediating, but applying the energy. Material from matter.