My children love to tie blankets round their necks and pretend to be all manner of different characters, but most of our blankets are big and they end up tripping on the edges and they come undone and fall off. Ages ago I shared a picture of some purchases from my local haberdashers which I had been able to visit on my own, the luxury of time meant I could choose carefully what I wanted. The satiny material I used to make capes. They have been worn a lot already.
They are simple design based on a circle. To ensure I bought the right amount of material I measured my children from the neck to a point that I wanted the cape to hang to. This gave me the radius of my circle which I doubled to make the diameter. I folded my material in four (in half, then half again) and using a pencil on a piece of string, the length of my radius, as a large compass I drew a quarter of a circle. If you are using satin material, as I was, make sure you pin the folded material together to prevent slipping. Keeping it pinned I cut it out and then cut out a quarter piece. I pinned the two pieces wrong sides together with two pieces of ribbon at appropriate places and sewed all but a short section of the cape. I turned it the right way out through the small section and hand sewed that up. A quick easy reversible cape!
If you were feeling inclined and the section is big enough you could make a hat with the piece you cut out....