This is No. 98 2478 Red/135 Green by Georges Vantongerloo. Created in 1936, the piece shows his pioneering use of a mathematical framework for abstraction. The first number, 98, is the catalogue number he gave the work. The remaining numbers—2478 for the red stripes and 135 for the green—encode how the vertical bands are spaced. Vantongerloo’s basic unit is a white rectangle with a coloured stripe to its right; he then counts these units from left to right, adding them cumulatively. In the green row you can see the sequence 1, 3, 5, and in the red row 2, 4, 7, 8. The result is a balanced, rhythmic grid that feels almost like a piece of mathematical prose. Oil on plywood, the canvas is a striking example of early 20th‑century geometric abstraction.
No. 98 2478 Red/135 Green is in the collection of Tate Modern on Bankside, London — free to enter. Point your phone at any artwork there and audioguide.london plays a free audio guide in six languages — no app download needed.