Creating limits stimulates ideas

Some exercises I learned from Art Lande and W.A. Mathieu were to make up short 'Pieces' on the piano using restricted means. Example: Make a piece using only one note. (note: these pieces, which were demonstrated in a classroom format generally lasted from 30 seconds to 2 minutes more or less). Make a piece using just the 'A's on the keyboard. Make a piece using only the notes A and E. And then expanding gradually on that, make a piece using only the left hand. Make a piece using only topmost and bottommost octaves of the piano. The list goes on and on. The idea is that limits stimulate creativity-- like Stravinsky's famous quote.