Possible to mesh a volume geometry with internal surface

[GeoGroup]

Dear Dr. Engwirda:
Thanks for your work, I have two problems.
(1) For a volume geometry with internal surface, like a box with a card in it, does it possible to be meshed using jigsaw. The image and file in format of stl are as follows.

(2) The code of Jigsaw is a little advanced for me. I am on a heavy study to under stand the code. Would you please add an example of using load file in the uni-test.

Best regards,

stl file link: https://github.com/GeoGroup/DigiSim/blob/master/mesh.stl