" Now I had discovered something even better - polymerisation depends on sharing. An atom which is short of an electron looks out for another atom that's got the right sort of electron (it's called covalency, for the chemically inclined), then the atom grabs the electron it needs. But no theft or nastiness is involved. Two atoms end up sharing the electron, and that's what holds all the atoms together in one beautiful long endlessly repeating dance - the beauty of glue! "

― Marina Lewycka , We Are All Made Of Glue