PHIRRATIONAL is the final project of an MA course of study, which engages in various ways with the phenomenon of the Golden Section. The work is aimed at describing the function and myth of this universal ratio of division, placing it in a spatial context and getting the public excited about it with the help of intriguing presentations. The irrational number 1.618…, known as the Golden Section, is universally present. It plays an important part in nature as well as in architecture, art and design. Elaborate spatial realisations of the principle of this phenomenon make it possible for it to be experienced in novel ways. While the first presentation is based on geometric bodies which are directly connected with the Golden Section, the second illustrates a fascinating example from biology – the arrangement of seeds in a pine cone.