[staringispolite]

Just verified this myself... pretty cool! I searched for the following:

  * Mutex lock (from the article)
  * Mutex lock C++
  * Python list comprehension

Third time's a charm! The prompt came up, and now I've got a simulated shell of sorts that looks a bit like linux but doesn't have most commands.

The main command is "request", which lets you request challenges through this shell. Requests are defined as follows:

  foobar:~/ guest$ help
  [snip]
  request	- request new challenge (of type 'tag') [tag]

  foobar:~/ guest$ tags
  Requesting tags...
  algo         	algorithms
  data_struct    	data structures
  low_level      	low-level representation (binary representations, endianness)
  math           	math
  crypto         	security and cryptography

Had a 2nd friend try the same who's not a coder, and it didn't work, so they're looking at more than very-recent search history.