Josef Albers1888–1976
Homage to the Square
German-American artist and Bauhaus teacher whose Homage to the Square series, from 1950, made nested squares into a study of how colours act on one another.
Squares inside squares, sitting low in the frame. Each step of tone is equal, and none of them look it.
After Josef Albers, Homage to the Square, from 1950

Albers spent twenty-five years on this format to show that a colour is never seen on its own. The steps here are exactly even, the same increment of tone between every pair of neighbours, and they will not read as even, because a band between two darker neighbours looks lighter than the same band between two lighter ones.
The squares sit low and slightly forward in the frame, which is Albers's placement, and it is what stops the set reading as a tunnel.
Behind the mathematics
Homage to the Square
German-American artist and Bauhaus teacher whose Homage to the Square series, from 1950, made nested squares into a study of how colours act on one another.