Related Clues:

• One is one
• Counting number
• Lionel train layout, often
• Shaped like some mirrors
• Stretched circle
• ___ Office (White House room)
• Like many an amphitheater
• Not a perfect circle
• Lionel train path, often
• Like most orbital paths
• Racetrack path
• Common Lionel layout
• Like a zero
• Sort of round
• Track configuration