The postal operations building in Lenzburg features bright, colourful building blocks made of aluminium, which mark the entrance area of the large structure. A total of 24 colours – six different shades of yellow, red, blue, and green each – radiate from the slat constructions between the columns in an inviting gesture, in playful contrast to the architecture’s clean lines. Visitors standing in the covered entrance zone can see the letters printed on the inward-facing side of the coloured boxes. Like in a game, they spell 24 different words describing the colour tones of the respective building blocks, including BUTTER (butter yellow), HIMMEL (sky blue), KORALLEN (coral red), and ENZIAN (gentian blue).

The artists Agatha Zobrist (1966, Aarau) and Theres Waeckerlin (1965, Basel) drew inspiration for their work from PTT advertising slogans from the 1990s (e.g. “My future is pink” or “My account is yellow”). They developed the play of colours and words even further by doubling the letter set based on the colour names and, like in the game Scrabble, composing new words from them – such as HIRN (brain), BELLEN (barking), and HERZEN (hearts). The words come together to form poetic phrases inside the covered entrance and determine the colour patterns visible from the outside.

The artwork was installed in 1997; the post office building itself was completed in 1984 according to plans by the renowned architect Jacques Schader. The proposal by Zobrist/Waeckerlin emerged as the winner of a competition with three invited participants organized by the Federal Art Commission in conjunction with the PTT Building Construction & Real Estate Department. The artist duo Zobrist/Waeckerlin worked together from 1992 to 2014, during which they realized several art-in-architecture projects in Switzerland.