Checkerboard and Checkers

This thing is a checkerboard. I have also included checkers, and arranged them so that you can print half red and half black. If you don't know how to play checkers,
http://boardgames.about.com/cs/checkersdraughts/ht/play_checkers.htm
has all the rules. Also, please look at the instructions to find out how to print this thing. This thing was made in OpenSCAD with the following code:
Board:
cube([42,42,1]);
translate([1,1,1])cube([5,5,1]);
translate([11,1,1])cube([5,5,1]);
translate([21,1,1])cube([5,5,1]);
translate([31,1,1])cube([5,5,1]);
translate([1,11,1])cube([5,5,1]);
translate([11,11,1])cube([5,5,1]);
translate([21,11,1])cube([5,5,1]);
translate([31,11,1])cube([5,5,1]);
translate([1,21,1])cube([5,5,1]);
translate([11,21,1])cube([5,5,1]);
translate([21,21,1])cube([5,5,1]);
translate([31,21,1])cube([5,5,1]);
translate([1,31,1])cube([5,5,1]);
translate([11,31,1])cube([5,5,1]);
translate([21,31,1])cube([5,5,1]);
translate([31,31,1])cube([5,5,1]);
translate([5,6,1])cube([5,5,1]);
translate([16,6,1])cube([5,5,1]);
translate([26,6,1])cube([5,5,1]);
translate([36,6,1])cube([5,5,1]);
translate([5,16,1])cube([5,5,1]);
translate([16,16,1])cube([5,5,1]);
translate([26,16,1])cube([5,5,1]);
translate([36,16,1])cube([5,5,1]);
translate([5,26,1])cube([5,5,1]);
translate([16,26,1])cube([5,5,1]);
translate([26,26,1])cube([5,5,1]);
translate([36,26,1])cube([5,5,1]);
translate([5,36,1])cube([5,5,1]);
translate([16,36,1])cube([5,5,1]);
translate([26,36,1])cube([5,5,1]);
translate([36,36,1])cube([5,5,1]);
Checker pieces:
union() {
difference() {
cylinder(3,4,4);
cylinder(1,3,3);
translate([0,0,2])cylinder(1,2.5,2.5);
translate([-0.5,0,2])cube([10,1,1]);
}
cylinder(1,2,2);
translate([0,0,2])cylinder(1,1.5,1.5);
}