Thanks, it was loosely based on a triop, a little like this:

http://t1.gstatic.com/images?q=tbn:A...pKp3OQk5bTRbE7

When I was designing I knew I wanted something a bit different, part of my brief was that it included some theatrical element to engage school kids and get them excited about building their own. Hopefully the tail / disk combo will do that.

PJ and I were having a think a wondered if there are any other machines with 2 active weapons?