Here's my first attempt at posting some 2DMath on this site.
First, I will paste directly from 2D output in a running Standard GUI Maple session.
Did it work, as the style guide suggests it would? No.
Now I'll try pasting into the popup that appears when clicking the "Maple Math" button in this mapleprimes editor. That didn't work, as the Insert and Cancel buttons on the popup stopped working as soon as I pasted in. I had to kill the popup.
Now I'll try entering markup tags, in the Mapleprime's editor's default mode (and not yet in the "Edit HTML Source" mode.
Now, as a last resort, I'll enter HTML editing mode in this Editor, and I'll put the "maple" start and finish markup tags in by hand.
None of all this produced 2D Math, at the time of my writing this. So may I ask, who has had success at this, and how?