A quality check on how evenly a rug's design mirrors itself, relevant to the many Persian and Oriental designs meant to be symmetrical: the medallion should sit at the true center, and corner pieces and other motifs should match each other and be spaced correctly. Handwork is never perfectly symmetrical, and exact repetition points to machine making; tribal and village weavers working from memory vary most, while workshop weavers following a drawn plan come closest to exactness. Noticeable lopsidedness lowers a rug's harmony and is one of the variables that affect its price.