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Bulletproof cladding for cars has a weakness, says David Adie of Frankfurt in GB 2 336 807. The hard ceramic armour pulverises a bullet when it strikes. But the armour itself cracks in the process, so if a second bullet hits the same spot it will go straight through. Adie’s idea is to use a sandwich of several ceramic sheets held together by fibre or plastic material. Each sheet is pre-scored with an array of grooves that mark out a tile-like pattern. When a bullet strikes, the sheet fractures cleanly at the grooves. The layered cladding ensures that the first bullet doesn’t create a weak spot for further shots.