" Why didn't I think of that genius idea?" This is the remarkable, at times funny, story of a young entrepreneur who, aged 18 and with $4,000 and no other funding, started up invisibobble - the revolutionary hair ties that have taken the haircare industry by storm. Today, Sophie Trelles-Tvede's company has sold over 100 million hair ties around the world and turns over $15 million. As a first-year university student, getting ready for a party, Sophie...