Zometool Green Lines Advanced struts add 30 new possible directions for each ball; provide more versatility and complexity Great for fans of Platonic or Archimidean solids, truncations, ruled surfaces, tetrahedral grids or octet-trusses These struts are also indispensable to build many structures of interest in Sacred Geometry Contains 222 precision-made components; a colorful instruction booklet; lifetime manufacturers warranty Zometool is the construction set that kids and Nobel Prize winners get hooked on