I made these two 3DS cases during a weekend of crochet inspiration at my friend's house. One is made from Red Heart Super Saver Earth & Sky, and the other is made from Caron Simply Soft Iris. Both of them are made with the same pattern.
This picture looks really neat if you scroll up and down while looking at it.
This pattern is worked in the round (continuous).
sc: single crochet
sl st: slip stitch
Round 1: Ch 24. Alternate start in 2nd hump from hook with 4 sc in last st, continue to the other side, 2 sc in last st.
Round 2: 2 sc in first st, sc in each st to the end of one side, 2 sc in last st, 2 sc in first st of the other side, sc in each st, 2 sc in last st.
Round 3: Begin shell stitch: sc in first st, skip 2 st, 5 dc in next st, skip 2 st. Continue the shell stitch around.
Round 4+: When you come to the first shell stitch, ensure you make the sc in the 3rd dc of the previous shell stitch, and the 5 dc should be in the sc. After you have done this a few rows you will know what to look for and automatically notice when you miss a stitch.
Round 5: When you have made the case fit the 3DS XL, end your shell stitches on one end of the case so you can start the flap. When you're ready to turn, either end on a sc or the third dc of one of the shells.
Row 1: If you ended on a sc, ch 3, turn, and sc into the same stitch, then 2 dc into the same stitch. Skip 2, and sc into the 3rd dc of the next shell. Continue with the shell stitch to the end of the row (and end with either a sc or the third dc).
If you ended with the third dc of the shell, ch 1, sc in first st, continue with shell stitch to the end of the row (and end with either a sc or the third dc).
Row 2+: Repeat row 1 as many times as you'd like for the flap.
On your last row, you can pause at any time and make the button loop by chaining. Sc to attach the chain to the piece where you stopped working, and check that the button just slips through without being too loose or tight. If it's too small, make a few more chains and if it's too big, just pull out some chains. Once it's the right size, continue with the shell stitch to the end of the row and finish off.
Affix the button with some thread and you're done!
Good luck with your project! Let me know if you have any questions!