You’ll need to sew a black fabric strip to the right-hand side of each t-shirt square. Then, lay out your t-shirts in rows of 3 to decide on your layout. The above pic is Layout #1.
Layout #2 is the picture above. I went ahead with Layout #2. It’s important to take a digital photo (camera/cell phone) or write down your layout, because once you start sewing shirts together, you’ll probably forget what went where.
Once you have your layout, sew the t-shirts together in rows. You will have 4 rows.
Once you have 4 rows, you’ll need to sew a black fabric strip on the left-hand side of each row. Please note that at this time, there are only black strips on the left and right of each t-shirt square. We will be adding the black strip/turquoise square rows in-between each t-shirt row as the next step.