What is this?

This is the image that none of my grandchildren was able to get in our quiz on Sunday in Grandad's School. Do you know what it is.
It has been a full on day - early morning walk before dawn, pilates, duets with Bill and then a long discussion with Wendy about various aspects of photography. She has persuaded me to contribute to the 20/20 Photo Book for the RPS Contemporary Photography Group (NE Region,) so a bit more work to do to pull together my contribution.