Remix of Gav's submission, but with the map cleaned up, fixed and resolved for easy laser cutting: partial triangles restored, layers are saved in the Adobe Illustrator version, colors are used to differentiate different line treatments in SVG and PDF versions. Should save you a bit of time and let you finish faster. SVG format shows a fill in preview mode because those line segments are open: adjust accordingly for your laser. .
Fits on one 12" x 24" panel, I used 1/8" birch plywood. Requires 3D printing the inserts that connect the corners.
Requires 60 small screws. You may want to adjust the size of the holes in the flat file and the part file to fit the screws you choose to use.