The original one was built by one intern[1], so it's quite possible so was this one. Not a huge resource suck when you are delegating one person to the job who just wants to learn.
[1] https://www.reddit.com/r/todayilearned/comments/3zfadv/til_t...
[1] https://www.reddit.com/r/todayilearned/comments/3zfadv/til_t...
This shouldn't be that surprising though, as Solitaire is in many ways a "flagship" app, which means it has to work on every single device that supports Windows 10 including tablets and phones and 35+ languages including right-to-left languages.