Vintage 1960s Women’s MAXI DRESS 4-6 White Blue Black Artsy Triangles Marimekko

Description

One-of-a-kind, vintage, maxi dress/cocktail dress/resort, hostess dress, circa 1960's/early 1970's, in an artsy, Op-Art, geometric pattern, of triangles, squares, triangular hearts.  May be a Marimekko?
Size says "10", definitely more of a 4-6 today - please check measurements.  100% heavy cotton, lined in white acetate.
Square neckline, sleeveless, with unique, 1.5" wide x 3" long straps at top of shoulders, empire-like waist, (seams, tailoring), zipper closure in back to waist.  23" high slits at both sides.  No pockets.
Excellent vintage condition, though some slight yellowing due to age; three, tiny stains on inside, lower lining, with loose lining hem in a couple of spots...still Stunning!  Has been dry cleaned.
Labels attached at inside neck say, "Size 10", and "Professionally Dry Clean Only". No brand or origin labels.
Approximate measurements:
• Length: 57"
• Sleeve openings: 8" high
• Underarm to underarm: 17"
• Bust: 28-30"
• Waist: 26"
• Hips: 36"
• Side Slits: 23"
Sold As-Is.