SHRDLU

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SHRDLU Help

About SHRDLU

SHRDLU is a natural language understanding program created by Terry Winograd at MIT in 1968-1970. It allows you to manipulate objects in a "blocks world" using English commands.

This is a simplified/modded version of SHRDLU and does not use color words in commands.

The name comes from the ETAOIN SHRDLU letter-frequency sequence used in old Linotype typesetting.

Read the SHRDLU wiki page

Sample Commands

Available Commands (Systematic)

• Move objects: put|place|move|stack the <size> <type> on|to the <size> <type>
• Move to table: move the <size> <type> to the table
• Ask support relation: what is on the table? or what is on the <size> <type>?
• Count objects: how many blocks|pyramids|balls are there?
• Yes/no support check: is the <size> <type> on the table? or is the <size> <type> on the <size> <type>?
• Tallest object query: what is the tallest block?

Object Types

• Blocks - Cubic objects that can be stacked
• Pyramids - Triangular objects (cannot support other objects)
• Balls - Spherical objects (cannot be stacked)

Properties

• Sizes: small, large

Physical Rules

• Objects can only be placed on blocks (not on pyramids or balls)
• An object must be smaller or similar in size to what it's placed on
• You can't pick up an object if something is on top of it
• Multiple objects can be on the table at once

Controls

• Mouse: Rotate camera by dragging
• Scroll: Zoom in/out
• Click object: Select and highlight

Tips

• Use type + size for specific objects (e.g., "the large block")
• You can use size adjectives to specify objects (e.g., "large", "small")
• If there are multiple matching objects, the system will tell you to be more specific
• The system understands context from previous commands
• Try asking questions about the world state
• Commands like "put", "place", "move", and "stack" are all synonyms for moving objects
• Use "on" to specify where to place objects (e.g., "on the table", "on the large block")