Materials: About 40-42 inches of cording and the fabric (see below)
I like the pattern because the bag stands up. This bag is not a standard color because I was using a fabric remnant I happened to have at home. Math bag colors are listed below.
Warning: these directions are ridiculously detailed. You will probably be able to skip lots of pictures once you catch the general idea of how the bag is made.
1. Make a pattern (I used newspaper) 9.5 inches by 20 inches. This seems large, but the finished product will be much smaller. Cut a piece of previously washed fabric (pink, green, blue, or yellow) using the pattern.
2. Iron 1/4 inch under along the longest edges.
3. Then iron under 1/4 inch on the short ends.
4. Sew the ironed edges all the way around the rectangle.
5. Fold the rectangle in half, right sides together.
6. Fold down each end, wrong sides together, one inch as shown below and press with an iron:
7. Sew close to the edge of the fabric making a casing for the drawstrings: 
8. Make another casing on the other end of the rectangle.
9. Fold fabric in half so the casings are right next to each other. The fabric will be right sides together. Sew a very narrow seam along the edge of the fabric, below the casing.
Sorry for the blurry photos. The one below shows that the casing edge was not sewn, leaving it open for the drawstrings.
10. Sew the other side in the same way.
11. Insert your hand in the wrong side out bag... 
...and bring the corner to a point with the seam running down the middle like this:
12. Using a straight edge, draw a pencil line across the end to make a triangle:
13. Sew along the pencil line. I started in the middle and went to the edge each time, but you don't have to do it that way--you can sew straight across. I find it to be a bit more accurate that way, though.
14. Press.
15. With pinking shears or regular scissors, cut excess material about 1/4 inch away from seam.
16. Repeat with other corner:
17. Pinch the opposite corners, making a line of fabric as shown:
18. Press:
Below: Lower edge is pressed.
19. Sew very close to the edge of pressed fabric:
That gives it a nice clean edge and helps it stand up better.
20. Repeat process with other edge.
17. Pinch the opposite corners, making a line of fabric as shown: 
18. Press:
Below: Lower edge is pressed.
19. Sew very close to the edge of pressed fabric:
That gives it a nice clean edge and helps it stand up better.
20. Repeat process with other edge.
21. Turn bag right side out:
22. Before cutting the cord in half, wrap some tape around the section to be cut. Cut through the tape. This will keep the cord from unraveling. Put a safety pin through one end of one of the cords.
23. Insert the safety pin into the end of a casing:
24. Move the cording through the casing to the opening at the other end.
25. Then insert the safety pin into the adjacent casing:
Now both ends are coming out of the same side:
26. Take the safety pin and put it through the end of the other piece of cording:
27. Start threading this cord through the end that has the loop:
28. Circle it around and put it through the adjacent casing:
22. Before cutting the cord in half, wrap some tape around the section to be cut. Cut through the tape. This will keep the cord from unraveling. Put a safety pin through one end of one of the cords.
23. Insert the safety pin into the end of a casing:
24. Move the cording through the casing to the opening at the other end.
25. Then insert the safety pin into the adjacent casing:
Now both ends are coming out of the same side:
26. Take the safety pin and put it through the end of the other piece of cording:
27. Start threading this cord through the end that has the loop:
28. Circle it around and put it through the adjacent casing:
It should look something like this after you finish threading the cording through the casings:
If you tighten the cords, they may seem too long. Feel free to adjust them to suit your needs. I tied mine into a square knot at each end.
Because I started out with longer cords than the size I recommended above, I ended up cutting some off:
There it is:
If you tighten the cords, they may seem too long. Feel free to adjust them to suit your needs. I tied mine into a square knot at each end.
Because I started out with longer cords than the size I recommended above, I ended up cutting some off:
There it is:
