The puzzle contains interlocking rails, that allow pieces to slide smoothly, but trap them inside the frame. When the puzzle is in its solved position, the 2x2 target block can slide out of the frame to reveal a hidden compartment inside.

The included assembly PDF contains instructions for two layouts, but you can mix and match the available pieces to create your own arrangements.

Version A

Also known as: Daughter in the Box, Huarong Dao, Forget-me-not

• 1x frame_center_hole.stl

• 1x target_box_2x2.stl

• 4x piece_1x2.stl

• 1x piece_2x1.stl

• 4x piece_1x1.stl

• (or simply print the pre-arranged version_A_all.stl)

Version B

Also known as: Pennant puzzle, Dad's Puzzler

• 1x frame_side_hole.stl

• 1x target_box_2x2.stl

• 4x piece_2x1.stl

• 2x piece_1x2.stl

• 2x piece_1x1.stl

• (or simply print the pre-arranged version_B_all.stl)

Note on 1x2 vs. 2x1 pieces: These are the same piece, just flipped upside down. If you are printing face-down on a textured build plate and want the texture to face the same way on every piece, use the specific files provided. If you don't care about the top/bottom orientation, you can use them interchangeably.

Printing

• The frame contains a 40mm bridge, so you may want to enable supports for that. All other pieces should print support-free.

• There is 0.4mm clearance between all pieces, so all pieces should move freely without needing any sanding.

• The 2x2 target box features a sliding dovetail lid. I've included three lid options: standard (0.4mm clearance), target_box_2x2_lid_tight.stl (0.2mm clearance) and target_box_2x2_lid_loose.stl (0.6mm clearance)

Assembly

Print all required pieces for your chosen layout, then either follow assembly instruction PDF, or make your own arrangement (start from solved state, then insert 2x2 target box, then scramble pieces into starting position)