SHRDLU can then answer questions about steeples in the blocks world, and build new ones.

This is an example of a SHRDLU session:

:Person: Pick up a big red block.
:Computer: OK.
:Person: Grasp the pyramid.
:Computer: I DON'T UNDERSTAND WHICH PYRAMID YOU MEAN.
:Person (changing their mind): Find a block which is taller than the one you are holding and put it into the box.
:Computer: BY "IT", I ASSUME YOU MEAN THE BLOCK WHICH IS TALLER THAN THE ONE I AM HOLDING.
:Computer:

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