For lack of a better term, let’s call this thing on the front of the doublet a “plastron“. I started with two layers of the yellow cotton, quilted together on the machine. The velvet was basted on the front side, wrapped around the edges and tacked down. I managed to squeeze a lining out of the remnants of the black linen and attached it by hand. Finally, I applied a border of red velvet ribbon:
I pinned it onto the doublet and played with the position a little. I think it will end up about here:
The belt in that picture is just a couple scraps of purple linen tied around. I’d like to do something involving black silk scarves, but I haven’t decided where to get them from yet. The current plan is to tack the corners down on one side, and fasten the other side with hooks and eyes I made from copper wire: