As galleries begin to open again this week I decided to check out two exhibitions currently on display at David Zwirner in Grafton Street. I booked ahead and cycled from home to Mayfair. Mask in place I made my way upstairs and was very glad I’d made the effort.

Bridget Riley has filled this airy space with her selection of ‘a group of working studies from the 1980s and 1990s that show the movement from ‘stripes’ to ‘rhomboids’.

What instantly appealed to me was the way these studies show how the artist develops an idea by starting off with stripes and then crossing these with diagonals which, to quote the gallery, ‘move the eye around, across and through the pictorial space’ and it’s this that leads to the ‘rhomboid’ paintings. Familiar with both in their finished condition, it is fascinating to see how these were intricate experiments planned out on annotated graph paper.

Riley’s fascination with – and reinterpretation of – the French post-impressionist and pointillist artist Georges Seurat is well known and it is not an enormous leap to imagine these as details from his paintings enlarged and formalised. But for me it’s the colours that aren’t on the paper that dance in the mind’s eye that I try to allow to take shape. The more I look the better the effect, like staring at one of those Magic Eye pictures back in the 1990s, but heaps more rewarding.

It looks deceptively easy. I have a hankering for some graph paper and coloured paints.