Our Wikipedia parser is pretty robust now, and the addition of Cascadia greatly simplifies the code. It's time to think about the actual gameplay.
The most important thing, the core of the game, is to create the riddle—asking the player to find a path from the initial article to the end article. We previously decided that in order to be sure that a path between two articles really exists, we will pre-crawl all the pages, from the first to the last. In order to navigate from one page to the next, we'll simply randomly pick one of the internal URLs.
We also mentioned including difficulty settings. We will use the common-sense assumption that the more links there are between the start article and the end article, the less related their subjects will be; and thus, the more difficult to identify the path between them, resulting in a more challenging level.
All right, time to get coding! For starters, create a new file inside the sixdegrees/ folder. Name it Gameplay.jl and...