Related Clues:

• Inventor's specialty
• Original thought
• Plan not yet on paper
• Think-tank output
• What's on your mind
• It can come to a head
• Start of a brilliant scheme
• Problem solver, perhaps
• Cortex product
• "What's the big __?"
• Use one's fingers, e.g.
• Have the belief
• Reason to shout 'Eureka!'
• Asset for an inventor
• You might bounce it off someone