/r/design-pattern/
to https://books.ikemo3.com/book/%E3%82%AA%E3%83%96%E3%82%B8%E3%82%A7%E3%82%AF%E3%83%88%E6%8C%87%E5%90%91%E3%81%AB%E3%81%8A%E3%81%91%E3%82%8B%E5%86%8D%E5%88%A9%E7%94%A8%E3%81%AE%E3%81%9F%E3%82%81%E3%81%AE%E3%83%87%E3%82%B6%E3%82%A4%E3%83%B3%E3%83%91%E3%82%BF%E3%83%BC%E3%83%B3/