I was originally planning to do a separate Instructable for the backpack, but decided it was pretty easy to make, and it would be hard for me to accommodate the different sizes of people, and the different functionalities. The one I made in this step is fairly functionless. I still have the option of adding a zipper on top, but don't have one at school (where I made it). Other people might want it to function like it does in the show, as the light green part being a flap that has one large black button.
Either way, if you're interested in making one, you can skip through the pictures, and read some newly added steps(below) and probably get a decent idea of how I did it, and base yours off of that.
1. Cut out the pieces.
- (x2) 14" circle (one of each color)
- (x4) 22" x 4" strip (2 of each color)
2. Cut some more...
- Cut each circle in half.
- Cut one light green, and one dark green in half, so you will have (x4) 11" x 4" strips, and (x2) 22" x 4 " strips.
3. Start sewing.
- Fold the smaller 11" strips in half (the long way) and sew along the edge. These will be parts of the straps.
- Pin each of the long 22" strips to the corresponding colored round edge of the half circle, and sew along that edge.
- Flip the 11" strips, so they're "right-side out", and insert each light green tube into each dark green tube, and sew them into place, attaching them to each other.
5. Top piece.
- Pin the straps onto the remaining half circle (I chose to start with the light green). Next, pin the other half of the light green top to the half circle with the straps you just pinned. Sew along the edge, finishing the top half of the pack.
6. Bottom piece.
- Do the same for the bottom half. Pin the straps in (making sure they aren't twisted), and sew it up.
- Now we need to sew across the middle of the pack, attaching the light and dark green parts. It's been inside out the whole time, so you need to leave about a 2 inch hole so you can flip the whole pack.
Hopefully those simply written steps and pictures can get you through it.