There are various ways of making these; the general idea is that you're making a soft cube, so you need six squares in some configuration, plus some space for the stitches to hold. I use two rectangles of suede for each ball, each 3 squares long (kind of like baseballs). You can also use three rectangles of two each, or two L-shaped pieces of 3 each. Or whatever else your little heart desires. All it really affects is the pattern of the colors.
1 red-orange and 1 sage green for each ball. The balls in my original set are filled with black beans, which produces a very pleasant noise. Now I'm trying to make some with jingly bells inside, which will sound sort of rattly when muted by the stuffing... kind of meh, but it'll provide variation. These are for use in juggling rhythms (I've gotten a bunch further since that video... exciting).
I'm using doubled thread to sew the edges together, with about 1/4"-1/2" of edging. As with most needle-and-thread projects, this is sewn inside out, except for an opening, then inverted and finished.
End of each rectangle attaches to the middle third of the other. Suede is a bit more finicky than the cloth I used before; I had to cut a small triangle from each straight edge where it folded around the corner of the other rectangle.
...and inverted. This is just to show what it should look like - a couple more sides need to be sewn before this can be finished. Not all my projects can be fantastic successes, and I ended up abandoning this ball because the suede was too thick and stiff to invert through the hole I had left, at least without undoing a lot of previous stitching. This also happened because I used smaller rectangles than before, which provides less leeway: 1.5-inch squares (so 5.5" x 2.5" rectangles, including 1/2" of slip), instead of 2-inch squares (7" x 3" rectangles). I didn't want to have to stitch up a whole side from the outside, as my attempts at "pretty stitches" usually produce the following:
These are the stitched-up holes from the first set, after stuffing the stuffing in. (Note on that: put in much more stuffing than you think you need, so that the ball is quite taut. Failure to do so will resort in a loose final product that expresses ennui, rather than exuberance. You want EXUBERANT BALLS.)
I'm happy sticking with these ones, as they are very aesthetically pleasing to me. Each has one rectangle of red-on-blue brocade, and for the other rectangle, they have burgundy suede, iridescent red/black cloth, and the reverse of the brocade (blue on red). Hey kids, patterning is cool. B)