The Haunch of Venison in London is currently exhibiting a collection of his paintings and sculptures. It's an amazing spectacle, seeing all this stuff together in one place.
For me, the highlights are his abstract paintings of concentric squares, of which there are many in collections around the world. This exhibition has half-a-dozen or so and its good to see them alongside each other, such as Gray Scramble (above).
Seeing them together enabled me to work out how the artist chooses his colour geometry. In Gray Scramble for example, alternate rings are taken from a gray palette and from a rainbow palette. The gray palette orders the shades from black through white, while the rainbow palette orders them from yellow through red to purple (or similar).
He uses the same sequences of colours and the same mechanism of interleaving in the other scramble pictures shown here. The total impact is overwhelming.