In the comment of an answer of this post: When can we take the Brillouin zone to be a sphere? , I tried to make a commutative diagram out of latex codes, but it seems we don't have the packages yet, can we install them?

"amscd" package codes is the one I used in the comment, it is simple but can only generate rectangular diagrams.

"tikz" package is much more powerful, but I haven't learn it.

Can we install both?

Update: Thanks to dimension10's answer, I realize it is a matter of MathJax, and there are versions of MathJax that support amscd, but no version supports tikz, see this post and this post. It seems our MathJax is below version 2.2 since my codes wouldn't get displayed as diagrams.

The rationale of asking for this is that it makes much less collective efforts to communicate, one user posts a diagrams, another user can just extract the codes and modify it, which is frequently needed in a discussion.