Alighiero e Boetti made his first ballpoint ink drawings in 1972–73 and continued through the late 1980s. Many of the works in this series contain puzzles, puns and linguistic codes, wherein letters of the alphabet run horizontally or vertically along the margin of the sheet. I sei sensi (The Six Senses) (1973), is part of a series of drawings done in code. An alphabet is laid out on the left side of the paper, forming an index. Commas, laid out horizontally, correspond to each letter of the alphabet. The “meaning” of the piece may be read by following the progressively arranged commas in relation to the letters. In the case of I sei sensi, Boetti has spelled out in Italian the five senses — vedere (to see), gustare (to taste), toccare (to touch), dire (to hear), odarare (to smell) — and one added by the artist: pensare (to think).