Cob windows

I’m in the early planning stages of our cob build and am curious about the organic shaped windows you often see. Are these windows square or rectangular windows that have cob applied to change the shape?
?

I’m asking in part because I know that often people use found materials for their cob windows which is great and beautiful but I would want at least the biggest windows to be double glazed so that I’m not sacrificing as much in terms of energy efficiency.

You may need to do some research across the internet or get a few books on the subject.
Page 216 of "The hand sculptured House" mensions a few points
- tape the edges of any glass sheet not in a frames to prevent slicing a finger
- insert glass about 6mm into the cob, trs enough, any more and it may break as the cob settles.
- If a window is in a frame its easier to have a freeform look because parts of the frame help the structure
- there are a few tricks in placing the window to create shade, reflect heat, drain water etc.

Thank you John!