In 1832, Rafinesque declared in his newsletter, the Atlantic Journal and Friend of Knowledge, that the dots and bars seen in Maya glyphs (like these at left, from the Dresden Codex) represented ...
In reality, there are all sorts of gotchas along the way. There are multiple types of glyphs, such as polygons, blanks, or compound glyphs. Sometimes, control points in the glyphs need to be inferred.