I need help to make a diagram(square), someone can teach me how to do?
I know that I could look at the posts to see a model, but I am stopped for 7 days to edit questions
Thanks in advance.
Even if you are stopped from editing questions for seven days, you can still see the MathJax code!
Right click on a math expression (for instance, that in Asaf's answer), in the context menu, select "show math as" -> "tex commands". This will bring up a pop-up window showing the MathJax expression that went into constructing that particular display.