When looking at the work, the gaze is immediately drawn to the centre, where the equation 'a = t' can be read in black letters on a light field. The square clearly stands out from the surrounding dense, black formations, which make the cardboard visible in various places and reveal a piebald, almost floral pattern. Four dashed lines running diagonally from the corners to the white-brownish field additionally draw the focus to the prominently placed combination of letters, which can be found many times in Tàpies's works: it not only represents the artist's initials and the first letter of his wife Teresa, but also evokes various associations. As the artist states: "I use the letters with very different meanings. A as a beginning, as a boundary, T as a stylisation of the Crucified and also as the initial of my name like an interaction of coordinates, etc." (Catoir 1997, p. 91)
Signs and letters have appeared repeatedly in Tàpies's work since the early 1950s. Besides A and T, M, R, S, V and X are recurring elements. The artist found inspiration, among other things, in the writings of the Catalan philosopher, logician and mystic Ramon Llull, whose medieval doctrine of the Ars magna provided a mechanical concept that served to find the truth through letter combinatorics. A and T simultaneously refer to the first two main figures from Llull's work 'Ars inventiva veritatis'.
