Sometimes I don't get a chance to get on here for a couple of days or so, but thanks to all of you for answering questions about the blocks.
My strips are 2.5 inches. I sewed two 2.5" strips together using a 1/4" seam allowance. Then, I sewed a 4.5" strip to those first two, to make the tube.
Somewhere on one of my strips, I messed up, and the two strips I sewed together didn't come out 4.5" inches. Always measure your two smaller strips to see what the width is, then cut the wider strip to that size.
You don't have to stick with 2.5" strips. I am excited to try smaller strips and larger strips and more than 3 strips, but that's just my crazy brain working overtime. I like to test out new stuff to see if it will work.
My squares are about 6 1/4", so if 4 blocks are sewn together, it would give you about a 12" block.