Related Clues:

• The 18 in a round of 18
• Makes invalid
• They may occur between generations
• Discontinuities
• Bridge spanners
• Diastemata
• Green targets
• Nullifes
• Spaces
• Emmental feature
• Some are black
• Leather features that are awl done
• Fissures, e.g.
• Places for aces
• Golf course features