TASK DEFINITION: Two analogies that signify affordances are given in the form "A : B. C : ?". Affordance is the possibility of an action being done on an object, for example book is an affordance of writing. The phrase "A : B" implies that B is an affordance of A. Your task is to replace the question mark (?) with the appropriate affordance of the given action C, following the "A : B" relation. Your answer should be a single object without further explanation.
PROBLEM: sing : song. wield : ?

SOLUTION: sword

PROBLEM: stir : soup. write : ?

SOLUTION: letter

PROBLEM: cure : disease. paint : ?

SOLUTION:
picture