Book excerpt: A celebrated teacher has gathered the tried-and-true techniques used by sculptors and folk artists, and tailored them for low-tech surroundings. Work with molds; form over armatures; model or carve with concrete; and treat concrete surfaces with mosaics, embedded objects, incising, and coloring. For dazzling outdoor embellishments, craft a birdbath, a Little Lady Fountain, and more. Twenty-five projects in all.