Box for Almost Impossible Heart puzzle

Created as a box for "Almost Impossible Heart".

It's essentially an import of the heart shape, which is then slightly oversized and cut out of the top and bottom halves of a box.

But it is parametric, and the OpenSCAD file can be used to import other STL files instead.

Could be fun as a Play-Doh mold.

Can adjust:
-height
-width
-depth
-size of bevel on top
-size of mating lip
-which .stl file is imported into the file
-amount to oversize the .stl cutout