Modular Magnetic Go Board Free 3D print model

This is my take on the worlds oldest continuously played board game Go. Dating back over 2000 years.
http://en.wikipedia.org/wiki/Go_game

This started out as a way to make a Go board that could be played in a moving vehicle, but it quickly morphed into what you see today. This modular set of Go board pieces can be used to create any n*n size Go board you want as well as arbitrary shapes. If really adds a new dimension to playing Go when you have obstacles or other shapes.

Each piece contains a 5 mm magnetic ball and is free to rotate inside the piece to create a perfect alignment with the center of the grid. I would imagine this board would be useful for people that lack the fine motor skills to accuracy place pieces on a standard Go board.

Video demonstration of board and pieces
http://www.youtube.com/watch?v=NZMIMVO_rrA

Print as many of each type of pieces as you need. The pieces should not require any sanding to fit together.

To create the grid pattern, I dissolved scrap abs plastic bits in acetone and mixed in a metallic purple pigment. I then used an acetone compatible syringe to fill the grid channel.

Use a flat tipped machine screw to insert the 5 mm magnetic balls.

Each field piece weighs around 3 grams using a 30 percent infill.
The Go stones were printed with 100% infill

I tried another method for finishing the pieces. I stuck a chopstick in the bottom of the pieces where the magnet goes and dipped it in a mixture of black abs and acetone. After the pieces dried a sanded the top, removing the top layer of black, exposing the pattern in the plastic from the extrusion process. This creates a neat repeating fractal like effect.
The fit was a little tighter due to the addition of the plastic