Day 3 was also a full day (with intermittent recipe experimentation). This day felt the longest, and was definitely the most tiring - there are quite a few (unattractive) photos of me lying exhausted across the half-finished quilt. Since I don't have a table surface large enough to fit most of my quilt on, I moved to my living room floor to be able to spread out. Ironing, however, was very precarious, and I would NOT recommend ironing directly on top of a rug.
Day 3 started off completing the border attachment from the night before. The strips were stitched together at a 135 degree angle, and the excess triangles were cut off. The completed front was layered on top of the batting and back fabric (also cut to approximately the same size).
In addition to ironing (and activating the adhesion of the batting), I pinned the layers together just to ensure that there would be no random fabric bubbles. Then, the tiring part - I went back over and stitched the layers together at all the borders of each shirt (and between the shirts and border).
Once all the layers were (finally!) stitched together, a 3" border was measured from the edge of the t-shirts and the quilt was cut to the final size. The corners were left as right angles.