Akara Granite Square
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Granite Square Ruler nwere elu anọ ziri ezi
A na-emepụta Granite Square Rulers n'ụzọ ziri ezi dịka ụkpụrụ ndị a si dị, yana iji nweta akara dị elu iji mezuo mkpa onye ọrụ niile, ma n'ụlọ ọrụ ma ọ bụ n'ime ụlọ ọrụ metrology.