Related Clues:

• Model
• It's unmetered
• Working model
• One of a multitude in a devil's-snuffbox
• Tough puzzle
• Way a fern reproduces
• Baffler
• Future fungus
• Plain writing
• Tricky problem
• Nonpoetic writing
• Baffling problem
• It may be blowing in the wind
• Tough nut
• Headscratcher