Throughout his career, Alighiero Boetti was fascinated by mathematics, specifically with models of multiplication. Its sets of rules on which games are based were key elements of his practice, as exemplified in the Bollini (Stickers) series. The series is based on a principle of symmetrical juxtaposition. The artist drew a square grid in ink on paper and placed colored stickers in each square such that the opposite sides of each square mirror each other. It was the intention of the artist to create various combinations, each one different from the next. Viewers who look closely, however, will discover this is not always the case. He repeated the same simple action of placing stickers as regularly as he could, thus conceiving his practice as an exhausting game of patience.