study 5-6 点を円形に配置する
https://scrapbox.io/files/68230b98b10de004b5483830.png
https://scrapbox.io/files/68230b938784006c13481aee.png
https://scrapbox.io/files/68230b959801054e20690df3.png
https://scrapbox.io/files/68230b9b8c2b69afa9359dc2.png
https://scrapbox.io/files/68230b9e3c956236bf99a755.png
https://scrapbox.io/files/68230ba309a2fbd76fa8ebe3.png
https://scrapbox.io/files/68230ba6fdb4aa441b71b32a.png