Powdered florist foam lets you create arrangements that resemble layered parfaits. Prepare a separate bowl of powder-and-water mixture for each color. Mix approximately 1 cup of powdered foam with about 1?2 cup of water, and stir well. Add more powder and water alternately until mixture reaches the consistency of stiff mashed potatoes. Spoon the first layer of foam into a glass, and compact it by pressing mixture down with a spoon; fill glass with additional layers. Insert leaves and flowers, and slowly add water. photo: Use sundae glasses to hold layers of moistened florist foam powder. Insert stems of leaves and flowers into the foam.