Related Clues:

• Third-degree
• Not flat
• Like some glasses
• Three-dimensional
• Measured in 3-D
• Having three dimensions
• Like some relations
• Like some measures
• Having height, width and depth, briefly
• Like the illusion of a mirage
• Like a Zollner illusion
• Like volume measure
• Raised to the third power
• Volume-based
• 3-D