I avoided this square because the construction is unconventional. Knit the bottom garter border then work the charts as columns, right to left, bottom to top, picking stitches up along the finished column edge to work the next column.
It seems the advantage here is that you only have to work one chart at a time, rather than working across 5 or 6 or more charts per row. But... this is square #16 for me and I had to work across multiple charts for practically every square leading up to this one so it felt a little... unnecessary. You could easily ignore the up down up down method and simply knit across all the charts at once. Just know what row you're on.
16 squares is all I plan to do for this afghan. I had enough yarn in the same dye lot for all 16 squares. I had to run out and buy four more balls to do the border with- it's a different dye lot but it shouldn't make too much of a noticeable difference since it will be for the border. I have to block the last few squares, then it's time to sew.