圆凿方枘（圓鑿方枘）　

◎ 圆凿方枘 yuánzáo-fāngruì

[like a square tenon for a round mortise——at variance with each other] 圆凿,指圆的卯眼;方枘,指方的榫头。圆孔不能容纳方榫头,比喻彼此不能相合