Union Quilt block is a little more involved than some of the other blocks recently. I wouldn't choose this block for you first or second quilt, but don't be afraid to give it a try. As always, you need to square up each section you sew.
I love the design you get in the center of the four blocks. You could change this block by adding a third color in the four corners. Actually, you could add a fifth or sixth color as ell. I will have to give that a try the next time I use the Union quilt block.
I have been quilting for close to 30 years and after loosing my job twelve years ago, I am now able to do what I love, QUILT! I specialize in baby quilts and have designed the "Lovie Lap Quilt" with pockets.