docker run --name=mediawiki_mysql \-e MYSQL_DATABASE=wikidb \-e MYSQL_USER=wikiuser \-e MYSQL_PASSWORD=mysecret \-e MYSQL_ROOT_PASSWORD=zhang123 \-v /var/mediawiki/mysql:/var/lib/mysql \-d mysql:5.7启动

I need to draw a background of layout as a triangle, like you can see in the picture.I've found an example where they do something similar, but I don't know how to adapt it to my case. Here is the exa