Some are lovely, some awful, some funny. Most of my ideas come from my own life in some way. But I wrote Big Brother when my daughter and son were little, from watching and thinking about the two of them. Every writer finds his or her own truth and ideas. And his or her own way to express these.
Ideas are everywhere.
It's finding a form to put them in that's difficult. That and time. The Park Book , with illustrations by H.A. Rey. It was published in 1944, a very long time ago. You can also see the park where I got most of the ideas for it, Washington Square Park, in New York City.