These are struts to supplement a Zometool kit. Zometool (http://zometool.com) provides struts in four different directions (orbits) relative to the icosahedral symmetry group of the Zome ball. An infinite number of other directions are possible. "Sand" is a direction defined in vZome (http://vzome.com), a software application for designing Zome models. In vZome, "sand" struts can be right-handed (appearing in the white triangles of the trackball) or left-handed (appearing in the black triangles). This model represents right-handed struts.