繩墨

lit. carpenter's straight line marker / same as 墨斗 / fig. rules / rules and regulations

rope / CL:根[gen1]

surname Mo / abbr. for 墨西哥[Mo4 xi1 ge1], Mexico

ink stick / China ink / CL:塊|块[kuai4] / corporal punishment consisting of tattooing characters on the victim's forehead

compasses, set square and straight line marker (idiom); fig. established standard / norms / criteria