Warmer days and another lighter suit.
Warning: Spoiler! (Click to show)
Looks great. That fabric is fantastic and the tailoring looks excellent. I think the square works well. The problem with many patterned squares paired with patterned jackets--at least to my eye--is that the density of pattern ends up being too similar. So you end up with too much visual information. Here, the figures on the square are spaced more widely than the checks on the jacket, so the patterns don't step on each other. And the green and red in the square play off the green and red in the jacket, while the navy on the square gives the square a bit of visual weight that keeps it quieter than the jacket, which it needs to be. No square would, of course, be fine. But I think this square adds to the whole.