black paper (art paper, not construction paper, which tears easily. Canson Mi-Teintes is a good choice.)
craft knife with a #11 blade and/or small, sharp scissors
old washcloth (to clean your fingers as you work)
pad of white paper, 11" × 14" (28cm × 36cm) or larger
The original expanded square exercise was introduced in a great little book titled Notan: The Dark-Light Principle of Design by Dorr Bothwell and Marlys Mayfield (Dover, 1991). The expanded square is only one of numerous exercises in the book, designed to give the reader/artist a better understanding of interactions of positive and negative space. There’s a good chance you’re already familiar ...