Following is a demo of the Challenge1.3.pl program.
?- talktome. Currently... the large yellow block is on the table the large red block is on the table the large blue block is on the table the large green block is on the table the small yellow block is on the table the small red block is on the table the small blue block is on the table the small green block is on the table What would you like to do next? |: this shouldn't be able to parse I couldn't understand that. Are you using proper words? What would you like to do next? |: stack the block on the red block. There is no block in your hand. What would you like to do next? |: stack the red block on the blue block. Currently... the large yellow block is on the table the large red block is on the large blue block the large blue block is on the table the large green block is on the table the small yellow block is on the table the small red block is on the table the small blue block is on the table the small green block is on the table What would you like to do next? |: pickup the large blue block. The block is currently under another block. What would you like to do next? |: exit. Exiting talktome... true