A version of one of these might work for your dilemma. Surely one of them can be tweaked to work for your window.

seeking information and specs on black window/door manufacturers that would work in multi-seasonal house

I have a weird shaped window that I am having difficulty solving. I need to be able to control the light, while still being able to see out. The room gets cold in winter (south facing), and hot in summer (gets sun early morning and late afternoon). I need to control the light so my fabric and paper don't fade, need the lovely even light for working, and have a lovely view from my desk. Venetians or vertical blinds would be perfect except for the angles. Any suggestions?

Hi, I'm trying to decide what to do about my window furnishings. I'm thinking in bedrooms to have sheers for privacy and then block out curtains for night, but don't really want double track as sticks out too much. Is it possible to have track inside window frame/recess? and is this a good idea? Any other ideas? It has been suggested I could go with a sheer blind for sun and privacy and curtains for blockout at night. In the rooms is also a wide but small window above window which will probably have a blind? Appreciate any advice