Lego makes a square brick and a cylindrical brick, each with just one peg and hole. What are the dimensions of these bricks? - Quora
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piece information - What are the dimensions of a LEGO brick? - Bricks
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piece information - What are the dimensions of a LEGO brick? - Bricks
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What is the interference lock offset of a LEGO stud/hole such that it fits snugly into another piece? (i.e. What are the snap mechanism dimensions?) - Quora