TITLE: Interactive web game for the word problem in groups?
QUESTION [9 upvotes]: I remember when I was in grad school, there was this website with a cool interactive game, where you were given certain "rules" (like 'abac=1'), and then you had to reduce a given word to the identity using those rules.  I remember it kept track of how many moves you made, and told you if you did it in the optimal number of moves or not.  I don't remember if it explicitly said you were doing group theory or not.  I remember the NY Group Theory Seminar page had a link to it, but that site seems to be dead now.
Anyone know what I'm talking about / have a link?

REPLY [5 votes]: The game's name is ExpaCon and was developed by Prof. Gilbert Baumslag. It is mentioned in this blog.
You can apparently download an Android app - see here.

Edit: Robert W. Bell's cv reads 

Developer and consultant for Expacon - a mathematical game based on
  group theory by Gilbert Baumslag

So in last resort you could try contacting him.