Related Clues:

• Power networks
• Furnace vents, perhaps
• Decorative gratings
• Radiator openings
• Crossword components
• Crossword parts
• Lattice patterns
• Crossword diagrams
• They get rough with the bars
• Gee, they're in the British Navy behind bars!
• They have a screen for what sounds harsh
• Sound as if they're rough sort of screens
• Riddles with rough rackets
• Things don't go so smoothly through them
• Graph-paper features