"Someone who lived beneath him used sometimes to hear a strange, phantomatic pit-apat from Klee’s studio above. Meeting Klee in the corridor, he asked if he had noticed it. 'So you heard it?”' said Klee. 'I’m terribly sorry. I was painting away, and it was going very well, suddenly I couldn’t help dancing.'” Paul Klee (quoted by John Russell in the New York Times ages ago)
….probably from creating a magical painting like this one, Fish Magic, 1925.