Cutest Scallop Coaster pattern

Well, I was expirmenting a bit this morning, and wanted to make some coasters, so I came up with this pattern. It has a really cute scallop around the edge, that I LOVE! I just want to make thousands of those little shells! So without further delay, here's the pattern:
Use any worsted weight yarn and the hook that is a comfortable size for you. And if any of you see any mistakes in the pattern, just let me know in the comments.
UPDATE: If you crochet tightly, change all Half double crochet to Double crochet and all single crochet to half double crochet to get the correct size. I've had a few people on Ravelry say that it turned out small, so go ahead and add extra rounds if needed and make it your own! If you crochet loosely, you should be fine following the pattern as is.
Rnd 1: Chain 4, join into a ring, chain 2, do 9 Half Double Crochet's into the ring, join.
Rnd 2: Chain 2, Do 2 Single Crochet's into each stitch around, join (18 stitch's)
Rnd 3: Chain 2, Do 2 Half Double Crochet's into each stitch around, join (36 stitch's)
You can keep it like this or do 1 more round and make the scallops.
To make the scallops, *Skip 1 stitch, do 4 half double crochet's into next stitch, skip 1 stitch, Slip stitch into next stitch*, Repeat from *to* 8 more times.
Finish off and weave in ends.
And you don't just have to use these for coasters, you could embelish a purse or use it as a granny square and connect them to make an afghan. That would be beautiful!
OH, If any of you are wondering about copy right issues, feel free to sell what you make with my patterns, but not the pattern itself. Thanks!
UPDATE: I just put this pattern on Ravelry. Please post your projects! :)