"A bend and a twist, then stretch and turn, now relax". What sounds like a series of exercise instructions, are also words that describe the various shapes a piece of DNA can assume. The classic double helix structure that one associates with DNA is but an extremely limited view of its physical 'shape'. The molecule that holds the codes of life is capable of further winding itself into myriad complex shapes called 'supercoils' that are capable of affecting gene expression patterns.