VRML housing feeds into health and population; population feeds into labour; labour feeds into food production and capital goods; capital goods feeds into consumption and capital; capital feeds into consumption; life expect- ancy feeds into health; health feeds into life expectancy; education feeds into life expectancy; population feeds into life expectancy; life expect- ency feeds into education; urbanization feeds into education; education feeds into transportation and job mobility; transportation feeds into pol- lution; housing drains resources; resources drain population; health drains day-care; sickness drains health; labour drains resources; capital drains labour; consumption drains surplus; surplus drains expenditure; ex- penditure drains goods; goods drains resources; resources drains food production; war drains food production; peace drains surplus; war drains life expectancy; mouth feeds into stomach; anus drains stomach; intestine feeds into anus; urethra drains bladder; semen feeds into penis; mouth feeds into vagina; vagina drains penis; penis feeds into anus; knives feed into flesh; flesh drains bullets; urbanization feeds into bullets; bullets drain population; education drains mouth; penis drains peace; semen drains life expectancy; death absorbs; life gives; art is long; life is short. (Clark and Cole, Global Simulation Models, A Comparative Study, 1975.)