Nicole Kada is a generally awesome person even outside puzzles and such.

**LASER CUT THE JIGSAW PUZZLE PIECES.** I started with a blank puzzle and then hand cut the top layer materials to match the puzzle shapes. When I tell you my materials, it may be more obvious why this was a very slow and painful process. Do not repeat my folly.

**Use highlight differentiated materials.** My testers--all two of them--found it difficult to distinguish between the two types of textured cardboard I used. There were other materials, but two of the materials I used with coated cardboard with different textures. Not different enough.

**Do not use felt.** Felt is nicely differentiated from other materials, and it's a popular crafting material, but when cut and then handled repeated times it becomes a mess.

**Do not use sandpaper.** It's great for yielding highly differentiated textures. Yet a total mess. And not good for blade edges.

**Use leathery textiles IF AND ONLY IF you can laser cut them.** I have some great leather cutting scissors now, but I wish I hadn't needed them.

**Do NOT start with a puzzle of more than 6 x 9 pieces.** Instead, start with as few pieces as possible. Like any product design task, implement the simplest thing that is a reasonable approximation of what you want, and then have people test that and give feedback. You'll get valid feedback on textures and other design considerations even with a puzzle of very few pieces.

Here are some design ideas that seemed to work, but that I wouldn't swear by:


* Create a puzzle of abstract shapes, with each shape having a distinct texture relative to the background texture. For example, I used (sigh) felt to create an oval, rectangle, and triangle. The felt formed the border, about 1cm thick. Inside of each shape I used (sigh) sandpaper of different grades. The background texture outside the shapes was smooth, corrugated cardboard.
* If you create abstract shapes, have each shape--oval, rectangle, triangle, whatever--span multiple puzzle pieces. Analogously, think of objects in picture-based jigsaw puzzles spanning multiple pieces.
* Add the occasional unique and/or very distinct feature, such as a raised bump on a single puzzle piece. The puzzler can then compare the relative position of that bump to the corners on the reference, and then estimate where the piece with the bump goes in the puzzle being completed.
* Attached the textured top layer to the puzzle base. I glued the top textured layers onto the cardboard below. This


Here are design principles that I would swear by:

* **Create a reference for the puzzle.** I made a complete duplicate of the tactile puzzle on thick cardboard. Just as a sighted person has the box photo as a reference, the BVI person should have a tactile reference of the completed puzzle.
* Make super double sure that handling can't damage a piece and alter its texture or knock off a protruding bit. This would be analogous to tearing the picture off a puzzle piece for sighted puzzlers.
* Just because one person completes the puzzle, doesn't mean everyone can. Assembling a puzzle by touch is a very different experience from assembling by sight.
* Create a short write-up explaining the starting strategy: find corners first; connect edges to edges, and edges to corners; then fill in. That I'm aware of, there are very few tactile jigsaw puzzles out there, so there's no history of passing along tips for completing puzzles.
* At least once a day, take some time and ask whether you are (or the team is) making decisions that reflect **sighted bias**.
* Don't make the puzzle purely tactual. Use high contrast colors. Most legally blind folks have at least some usable vision. Ensure the puzzle works for the largest possible group.
* Get feedback as soon as possible. Discuss every stage of ideation, development, and prototype with local members of the BVI community, or with BVI students. Do not simply gather data, create the puzzle, and then present it at the very end of the project. Test multiple prototypes, gather feedback, and keep refining.


As soon as possible, talk with local BVI folks. Bring materials of different textures. Take good notes, and incorporate ideas from your future puzzlers. Make them part of the team.