The Piero of the title is Piero Della Francesca, whose Baptism of Christ was the starting point for this painting. This work uses the Baptism’s underlying grid of thirds to organise the composition. We are transferred to the hilly background of Piero’s painting, and that landscape is transposed to one of London’s best viewpoints. If you look carefully, you might be able to see the final transpositional touch: the dove is transformed into an aircraft, climbing past the post office tower.