You basically crochet a doily or table cloth and stretch it inside a hoop. (we used to make them in the 1970ties, but with white cotton and a very small hook size, so they ended up much smaller, to hang in the window).
My biggest problem was to find a VERY LARGE ring to fit this. Needed to be at least 100cm (40") in diameter. I only found 1 place online and it was close to $100. Little too pricey for my taste.
Many people gave me suggestions and eventually I went with connecting 2 hula hoops and spray paint. I used up practically all the yarn and it made the mandala diameter 110cm (43").
I'm not completely satisfied with the spray paint. Suppose to be for plastic but here and there it didn't stick very well so there are specks of bright pink hula hoop showing through. I'll have to touch that up. But you can't see it from a distance so overall I'm very pleased with the result.
As a lucky coincidence the blue mandala matches my Persian tile blanket hanging on the railing. I had not planned it like that, only noticed it when it was on the wall.
This is the Meu Mundo Mandala and you can find the pattern graph for free on the internet.
I have since made more mandalas, some in different designs.
I've discovered some better options to wrap the hula hoops, sticky burlap tape or hockey tape. Last one is a little stretchy and available in many colours!
Peacock Mandala in Scheepjes Whirl 776 Rosewater Cocktail
Celestial Mandala in Scheepjes Whirl 788 Night Time Bubbles
And 2 more Meu Mundo Mandalas
Hangs in my daughters massage therapy clinic.
Scheepjes Whirl 778 Turkish Delight.
I worked on that one in the car on our trip to the Maritime provinces. It's going to be a wedding gift for my nephew and his wife!