四个三角形拼一个菱形◇https://blog.csdn.net/qq_34382449/article/details/81234653?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522165033417616782248560145%2522%252C%2522scm%2522%253A%252220140713.130102334..%2522%257D&request_id=165033417616782248560145&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~blog~top_positive~default-1-81234653.nonecase&utm_term=css%E4%B8%89%E8%A7%92%E5%BD%A2&spm=1018.2226.3001.4450
