1. Regular tetrahedral A regular tetrahedron has 4 bonds each extending from the center at an angel of 109°28'.Two of them are 'Horn'shaped and work as male(+)for connection. The remaining two work as female(-)using the holes. Female Bonds can be turned into male by inserting Connector ORG-20 into the holes. Some lubricant may help for the insertion.(*) Connecting one part to another with connectors will form a chain hydrocarbon. Bond length is the same in these parts. Accuracy may be enough for simply viewing shape of a molecule. (*)Sewing machine lubricant is recommended, but any other lubricant can be used. Apply some lubricant where connection is tight. Model pieces are resistant to chemicals.