Roses are red, violets are blue but according to the latest understanding these colours are really an illusion. One that you create yourself. 　　Horizon reveals a surprising truth about how we all see the world. You may think a rose is red, the sky is blue and the grass is green, but it now seems that the colours you see may not always be the same as the colours I see. Your age, sex and even mood can affect how you experience colours. 　　Scientists have unlocked the hidden power that colours can have over your life - how red can make you a winner, how blue makes time speed up, and more.