I know this is going to be hard to believe but, YOU CAN MAKE YOUR OWN pattern!
I suggest starting with a piece of paper 8-1/2" x 11" (standard typing paper) or the size you want. And draw a grid all over it using a pencil and ruler. You might start with using 1" squares or what ever works to get the number of pieces you want the puzzle to have. Then free hand the squiggle lines between the corners of the grid with the pencil and then darken the lines with a black ballpoint pen to make the pattern. Oh yes you can draw worth a darn ! Just give it a try before you cry.
OR... You can just cut the pattern freehand with the saw. Yes, that can be done too...I've done it!