Ah, but if it's been done before, isn't it a challenge to do it differently the next time? Maybe if we had the same challenge each week it would soon be impossible?
Perhaps I didn't put the first bit well. I walk about looking all the time. Every now and then I see something I hadn't come across before or I am seeing in a new way, and think 'yes, that's going to look good'. For me it's about keeping alert to new possibilities.