Youngsters meet up on the village outskirts, racing their tractorcars, a Swedish term for an older car converted for use as an agricultural machine. The smell of rubber, oil and souped-up engines fills the air when the engines speed. The cars form into a circle as the boys take turns in the middle. It is a game - showing their skills - showing off to the girls. Strength is measured and proved - as if in a strange ritual mating dance. Leading Swedish photographer Martin Borgen offers a fascinating insight into a little-known aspect of European youth culture.