Recently I have been totally absorbed in transparent window stars AKA Waldorf Stars. On browsing one page, I noticed an origami folding mat which looked pretty handy for folding little pieces of paper. I looked around online and not finding anything else similar decided to make my own. I had to fuss with Excel a good bit to get it as square as possible, but I finally think I got it as close to square as possible. Print on cardstock for more stability.
(Click image to download .pdf file)
So we had a baseball mitt, something of a bat, but nothing in the line of a ball. My darling children made a ball from yarn and a plastic bag (complete with huge piece of gravel inside! 
Small rock or stone for center weight
Newspaper to coat the rock (remember rock, paper, scissors? … paper wraps the rock, lol)
Polyfill
Yarn
Yarn needle
Baseball stitching pattern (optional)
Begin by wrapping the stone(s) with newspaper, then cover the newspaper with a layer of polyfill or quilt batting. Wrap snugly with yarn and keep wrapping, turning the ball constantly to keep the shape nice and round until you reach the desired size. To keep the yarn from unwinding, string some of the yarn onto the needle and sew in and out all around the ball to anchor the layers of yarn. Optionally, you can print out a baseball stitching pattern and stitch along that to make it look a little more authentic looking.
The kids love their new ball. It’s a little bouncy (but not overly), it is a good size for playing catch, and it’s soft enough that it won’t cause any injuries to inexperienced ball players. Mission accomplished.
