Details from Coventry Cathedral website:

The artist John Piper was asked to design the stained glass. His view was that with 198 small areas of window to fill, the glass needed dazzling colour and an abstract pattern to create unity.

Working with glassmaker Patrick Reyntiens, he created the window from thousands of differently-sized pieces of glass to visually vary the space and rest the eye.

The baptismal font is situated in front of the baptistery window and is carved in the shape of a shell. The Inner City Peace Trail provides further information:

The font is carved into a boulder that was donated by the government of Jordan as a gesture towards Muslim, Christian and Jewish cooperation. It was shipped from a hillside near Bethlehem in 1960 and placed before John Piper’s stunning Baptistry window.

The font was carved into it by Ralph Beyer. He was a German letter-cutter, sculptor and teacher. He is most noted for his work on the new Coventry Cathedral, including carving not only the baptismal font but also the foundation stone of the cathedral, the greetings set into its floor and, what is perhaps his most famous work, the huge inscriptions in the nave.

Born in Berlin, Beyer served in the British Army during WWII. His mother was murdered in Auschwitz.