Query: Why did publisher change the cover picture on Feynman's book?
Context: He wanted a picture of a drumhead sprinkled with powder to show the modes of vibration at the beginning of the book. Concerned over the connections to drugs and rock and roll that could be made from the image, the publishers changed the cover to plain red, though they included a picture of him playing drums in the foreword. The Feynman Lectures on Physics occupied two physicists, Robert B. Leighton and Matthew Sands, as part-time co-authors for several years.