Here is a puzzle activity for reviewing equation solving. I found that it worked better when I made an answer mat for students to put their pieces onto (I indicated a couple of pieces on the mat to help them align the rest of their pieces).
Here are two files in Pages and Word that you can work from to make your own.
A comment from David Wees in a previous post with a similar puzzle I did for quadratics:
Yeah your puzzle is cool. So cool that I've created a random generator in Adobe Flex.
See my algebra puzzle generator.
There is an app called Formulator Tarsia that will do this, but it only works for Windows (which I don't have access to) so I haven't tried it out. Give it a try!