Etty Darwin and the four pebble problem

"Etty loves make-believe. Her dad loves science. Etty believes in fairies. Her dad would need to see some proof that they exist. But they both love nature, conversation and each other. A gorgeous rumination on belief and imagination featuring Henrietta (Etty) Darwin and her famous father, Charles. Etty went on to become a valued and keen editor of Charles's work and a thoughtful and intellectual being in her own right. This imagined conversation between Etty and Charles as they stroll around Charles's real-life 'thinking track' explores their close relationship and shows that even science is nothing without an open mind and imagination"--From the publisher's web site.