Question mark
In the early 13th century, when the growth of communities of scholars (universities) in Paris and other major cities led to an expansion and streamlining of the book-production trade, punctuation was rationalized by assigning Alcuin's stroke-over-dot specifically to interrogatives; by this time the stroke was more sharply curved and can easily be recognized as the modern question mark.
Tag system
According to a footnote in Post 1943, B. P. Gill suggested the name for an earlier variant of the problem in which the first "m" symbols are left untouched, but rather a check mark indicating the current position moves to the right by "m" symbols every step. The name for the problem of determining whether or not the check mark ever touches the end of the sequence was then dubbed the "problem of tag", referring to the children's game of tag.