Apart from the little hiccups, this was a great one! Took quite a while but it was most fascinating.

I was able to figure it out, eventually. I didn't memoize generics with around properly. Now I'm doing the errors and ... I'm lost. But I suppose I'll get to it eventually.

Another thing I noticed was that the "Times" section of a Kata is not adding very much and I cheated the system unwillingly. When doing a Kata offline within your own editor, the time will not get counted. I mean, I might now JavaScript a little, but writing an Interpreter in a few seconds is not one of my skills. ;)

I would like to see the 'up vote' button next to the 'mark as favorite' button. Most of the times, when I star something, I also like to up vote it and from my point of view it makes sense to group those two together.

Love the description. :)

This was mind bending, I really enjoyed it. :)

Sorry, I really don't get what this Kata is asking me to do.

I was stuck at exactly the same spot, but I don't know how to describe it without spoiling anything.