Pattern: "Falling Star" by Melinda Miller.
This was an easy pattern, but it is a great example of a square that needs to be blocked to straighten out the edges. If I were to make this square again, I would decrease the number of sc stitches in the corners of the third round that I worked in white. And I'd probably try corners in the last two rounds of 1 dc, ch 2, 1 dc.
This is how I block my squares when necessary. Instead of a fancy (and expensive) blocking board, I use a sheet of 1/4" thick white craft foam. The sheets are sold in 18" x 24" pieces, so you can fit several smaller squares at once. I start by stretching out one side until it seems to lie flat without much distortion, then I pin the two corners down to the foam.
Then I fill it in along the side with enough pins to keep the side straight. Start in the middle of the side or you'll find that it pulls to one corner! By this I mean that you need to pull the middle of the side (check out the one below to the right) down to the middle of your straight line and pin it in place, then even out the rest of the side and pin in place.
I straighten out each side in this manner, then spray with water from a bottle I keep handy. If I'm super patient, I wait for it to dry naturally. If not, I lay a towel over it and soak up the water and pretty much immediately unpin the square.
Note: my initial idea for using the foam for a blocking board was to adhere two sheets of it together for a 1/2" thickness, but I haven't done that yet and although the holes don't really heal themselves, the two pieces of foam I bought over a year ago have lasted through hundreds of squares! If you do it my way, just make sure you aren't ruining your good tabletop with pins that may poke through a little.