OCO explores the three-dimensional architecture of the letters O, C, and I, and the multiple meanings (in Portuguese) that emerge when the letter I rhythmically appears and disappears. These meanings emerge through the cognitive associations made by the viewer as well as the perceived spatial relationships between the letters. Originally presented in 1985 as an interactive holopoem (lost), OCO was recreated in 1990 as an interactive digital poem. OCO is presented here as video documentation of an interactive reading experience.