continually been used as a symbol for atoms.
All colorways for this design: Red (http://www.spoonflower.com/fabric/1766894) Orange (http://www.spoonflower.com/fabric/1766901) Yellow (http://www.spoonflower.com/fabric/1766886) Green (http://www.spoonflower.com/fabric/1766906) Blue (http://www.spoonflower.com/fabric/1766885) Purple (http://www.spoonflower.com/fabric/1766895) Multicolor (http://www.spoonflower.com/fabric/3035579)