The small glass seed beads that are popularly associated with American Indians were not widely available in the Columbia River Plateau until the 1860s. After they arrived in the region in quantity and diversity of color, they encouraged the creation of regional styles of both geometric and figurative decoration. The earliest known examples of Plateau pictorial beadwork show floral designs and horse imagery. Other early subjects included deer, elk and birds. These motifs were generally simply arranged upon light-colored—often white or blue—backgrounds. The symmetrical design and use of opposing male and female animals is a design convention that is often seen on beaded Plateau vests.