Problem
Windows with a sharp edge where the frame meets the wall create harsh, blinding glare, and make the rooms they serve uncomfortable.
Solution
Make the window frame a deep, splayed edge: about a foot wide and splayed at about 50 to 60 degrees to the plane of the window, so that the gentle gradient of daylight gives a smooth transition between the light of the window and the dark of the inner wall.
Related Patterns
… this pattern helps to complete the work of Light on Two Sides of Every Room (159), by going even further to reduce glare; and it helps to shape the Frames as Thickened Edges (225).
Build the depth of the frame so that it is continuous with the structure of the walls - Frames as Thickened Edges (225); if the wall is thin, make up the necessary depth for the reveal on the inside face of the wall, with bookshelves, closets or other Thick Walls (197); embellish the edge of the window even further, to make light even softer, with lace work, tracery, and climbing plants - Filtered Light (238), Half-Inch Trim (240), Climbing Plants (246) …
Alexander, Christopher. A Pattern Language: Towns, Buildings, Construction. Oxford University Press, 1977, p. 1053.