# Jigsaw possible?

A light jigsaw puzzle.

Start with a square. Assume two adjacent sides (top and left) are always straight and the other two adjacent sides (bottom and right) can be either straight, convex or concave. That gives $$3 \times 3 = 9$$ possible squares. Below we see $$3$$ example squares where the bottom is straight.

Is it possible to create a $$3 \times 3$$ jigsaw puzzle (outside borders straight) with these $$9$$ pieces? Rotation of pieces is allowed, but flipping of pieces is not.

I think

this does it:

+---+---+---+
|   >   |   |
+-v-+-v-+---+
|   >   |   |
+---+---+-^-+
|   >   |   |
+---+---+---+

having the correct inventory of: one with two lumps, one with two dips, two with one of each (in the two different orientations), two with one lump, two with one dip, one with none.

Here's one possible solution:

 ------- ------- -------
|       |       |       |
|       |       C       |
|       |       |       |
------- ------- -------
|       |       |       |
|       |       C       |
|       |       |       |
---U--- ---U--- ---U---
|       |       |       |
|       |       C       |
|       |       |       |
------- ------- ------- 

• I beat you by one second :-). Feb 24, 2020 at 1:35
• @GarethMcCaughan May I ask how you got the spoiler to work with the code? Feb 24, 2020 at 1:50
• By using <pre>...</pre> at start and end, and putting >! at the start of each line. Feb 24, 2020 at 1:59
• @user3574641; if you want to know how something is done, there is a 'edit' button at the base of each post - click it and you can see the post's source text.
– JMP
Feb 25, 2020 at 6:33
• Thanks a lot, I didn't realize that was possible on other people's posts. Feb 25, 2020 at 17:07

A different structure:

 +---+---+---+
|   >   |   |
+-v-+-v-+---+
|   |   >   |
+---+---+-^-+
|   >   |   |
+---+---+---+