surface
以下スタディ
https://gyazo.com/b690c879c40a0200de61fa2fbcc82dec
https://gyazo.com/9c1c70ecd0be2aadcb0701d1a6eaa02dhttps://gyazo.com/670b07c22011571b06748d3c23b14324
https://gyazo.com/a4bbc873ce05af2c95257b89a7bddaf0https://gyazo.com/3b6eb96fd26da00a8712f7b09bbbbf1c