see 枘鑿|枘凿[rui4 zao2]

incompatible (abbr. for 方枘圓鑿|方枘圆凿[fang1 rui4 yuan2 zao2]); (literary) compatible (lit. "mortise and tenon")

see 方枘圓鑿|方枘圆凿[fang1 rui4 yuan2 zao2]

(lit.) like a square peg in a round hole (idiom); (fig.) incompatible