This is what I came up with trying to make a sunbonnet pattern. I rounded the corners using a protractor.
I sewed the three front pieces then turned and quilted every inch.
I then folded the ties as if I was making double fold bias tape and sewed down each side.
Next I hemmed the cape.
After that I gathered the raw edge and sewed to the short side of the crown.
With the ties sewn on.
And lastly I gathered the crown and sewed it to the front.
Now I have a sunbonnet.