From 1966 Oiticica’s art extended the ideas he had begun to explore in the Bólides, Parangolés and Penetrables. His work began to make greater use of appropriation and often took the form of multi-sensory environments or events. But he did not abandon his interest in colour, and in the late 1970s he returned to his investigations on the subject with a series of architectural models, or maquettes, which he called ‘Invention of Colour’.
These constructions were conceived as large, open-air Penetrables, like the Hunting Dogs Project of 1961. The squares (which for Oiticica signified both a geometric figure and a piazza) consisted of a configuration of fixed or flexible square planes, painted in primary colours and in white. Floors of white sand were designed to reflect the colour of the panels and the sunlight.