Joint distribution of number of crossings and longest run.
The inner workings of crossrun are described in this article in PLOS ONE, https://journals.plos.org/plosone/article/comments?id=10.1371/journal.pone.0223233 . A non-technical description of the article is available at Science Trends, https://sciencetrends.com/improving-tools-for-quality-improvement-crossings-runs-and-crossrun/ .