wind braces

 In architecture, wind braces are diagonal braces to tie the rafters of a roof together and prevent racking. In medieval roofs they are arched, and run from the principal rafters to catch the purlins.[1]

Trelystan Church, Montgomeryshire. Decorative arched wind braces between purlins- 15th-16th century

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 Metasyntactic variable, which is released under the 
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