function (run rules) [flour sugar apples]
  (> (apple cake)) (run rules)
end 

function (run rules) [apples oranges cherries]
  (> (fruit salad)) (run rules)
end

function (run rules) [(fruit salad) (apple cake)]
  (> (fruit cake)) (run rules)
end

function (run rules) []
end

(> sugar)  (> oranges)
(> apples) (> cherries) 
(> flour)  (> apples) 
(run rules)
