ConceptNet
An encyclopedia of concept simulations that computers and humans can learn from.
An experimental project in machine learning.

flap
to move up and down.

crumble
break or fall apart into small fragments, especially over a period of time as part of a process of deterioration

crush
to damage something by squeezing it very hard.

cliff
the high, steep side of a mountain or rock.

meet
to come face-to-face with another person

drip
to fall slowly, drop by drop.

stack
a pile of things, one on top of another.

sort
to arrange things into different types or groups.

cover
to put something over or on something else.