Related Clues:

• ...
• Start of an invention
• Inventor's ''step one''
• Bright one from gray matter
• Heavenly circle
• Overhead light?
• Inventor's start
• Light bulb's signification, in cartoons
• Light bulb, in comics
• Mental glimmer
• Object of thought
• Good indication?
• Head piece?
• Surrounding light
• Ring up?