They make thick woven fabric vertical blinds. I used them for a stock broker's new offices to solve acoustics at the glass perimeter: angled half way closed avoided sound reflections and caught reflected sound from behind yet maintained a sideways view of St. Patrick's Cathedral, etc. They worked quite well.
Their prior location, across the street, black metal horizontal blinds, fully closed, looked like the black hole of Calcutta (whatever that is), might as well have been in a basement.
Their prior location, across the street, black metal horizontal blinds, fully closed, looked like the black hole of Calcutta (whatever that is), might as well have been in a basement.