Buttons Puzzle Game!

This is an interesting game, created on 15th March 2002. with the code taken from my CS5232 textbook Formal object-oriented specification using Object-Z, Roger Duke and Gordon Rose, Macmillan, 2000

Hope that you find some fun playing it! :)

Instruction Click on any one of the boxes and that square and its neighbouring squares to its top, bottom, left and right will be highlighted. Click them again will toggle them. Each click then toggles from one color to the next.
The aim is to make all the squares turn black. Refresh your browser to start over!