In the "self-intersecting reflexicon" below, one can indeed find thirteen e's, five f's, four h's, five i's, four n's, four o's, seven r's, thirteen s's, six t's, three u's, three v's, one x,. More remarkably, only twelve letters of the alphabet are used: one appearing on each of the twelve intersections created! The layout is far from unique, though experiment suggests a specimen using eleven or fewer letters is extremely unlikely.
"A Self-Enumerating Crossword,"
Word Ways: Vol. 20
, Article 4.
Available at: https://digitalcommons.butler.edu/wordways/vol20/iss2/4