Rare vintage rayon dress with triskelion design

I scoured the internet looking for another of these and could not find one. This is a beautiful, well made garment. It features princess seaming, handkerchief hem, side seam pockets, and inside French seams (where the inside raw edges are enclosed in the seam for comfort and durability).
Size tag says M/L.
Note: There is one tiny spot on the lower part of the skirt where it looks like the fabric snagged on something and pulled a couple of threads out like a tiny loop. It's not quite a hole, just threads sticking out. I tried to show it in one of the photos but it's kind of hard to see. It is a very small flaw and not even noticeable when the dress is being worn. I just want to give full disclosure.
Other than that the dress is in excellent condition.

Measurements with dress laying flat- in inches:

Bust - 22

Waist - 21

Hip - 25

Sleeve length from the shoulder seam - 23

Shoulder seam to shoulder seam across back - 18 1/2

Back length from neckline - 52 1/2
Note - the handkerchief hem at the bottom of the dress is about 4 inches longer on the sides than it is in the center, making for a total length of 56 1/2 (or 4 feet 8 1/2 inches. I estimate that if you are 5 feet 8 1/2 inches tall, you should be able to wear this with flat shoes. If you are shorter, you're going to need shoes with some height