Thirty years later, when Cervone created MathJax, I was amazed again—though perhaps not for the right reasons. I had supposed that the major programming challenge would be capturing all the finicky rules and heuristics for building up math expressions—placing and sizing superscripts, adjusting the height and width of parentheses or a radical sign to match the dimensions of the expression enclosed, spacing and aligning the elements of a matrix. Those are indeed nontrivial tasks, but they are just the beginning. My recent adventures have helped me see that another major challenge is making TeX work in an alien environment. — MathJax turns 3.0