I designed this to be an interlocking grid for Qwirkle.  The outer edge walls are half the width of the interior walls so all the spacing is equal when you link two boards together.  I printed six boards, but depending on the game layout, you could need more.  It helps from a bad bump ruining the whole thing.  I minimized the grid to reduce the print time and wasted plastic.

Six boards will fit in the box, but the lid won't go down all the way.