And then edited to make one side of the jigsaw cutter sharp.
You can make Jigsaw's of arbitrary size and shape by using the inkscape extension and a bit of manual editing. (Use the example scad as a guide) :)
Takes a while to F6...
and made one in OpenSCAD with my Inkscape extension - originally designed for laser cutters.
3d model print parameters
Choose the top and bottom line widths to better suit your print res.
How I Designed This
The ou...tline intially comes in as a solid block. So you could Minkowski your way around it. But if you look at the file you can see what I did - which was to cut and paste some code from one of the other outlines - and replace the 4207 entity with a hulled line instead of a linear_extrude. If you edit the file you can make the walls higher, or wider. All parameters are exposed at the top. For more shapes, sizes, interlocking options - make it again in inkscape.