Estimating materials for this piece was very important. The last thing you want is to run out of the primary colors in the composition. 5 boxes of premium pastels at 72 pcs. Per box and add a mixture of water, corn starch and food dye to start a base, then move in with the chalk for the real work. All this chalk in Detroit’s own Hart Plaza during the the festivities of the Movement 2010 should be interesting!