Related Clues:

• Fingerprint or dropped handkerchief, say
• Inventive thought
• Something to think about
• Suggestion
• Designer's need
• This, for example
• Detective's need
• Print, maybe
• It may be found with a magnifying glass
• Point of view
• Brainwave
• See 2-Down
• 'I had no ___!'
• Guiding light?
• Inkling