Not 100% sure of the window and layout of 490, but generally windows of living rooms for all units should be bay windows except for those in the bedrooms. 490 & 487 r the 2 blocks thatfaces more to the east and west than the rest of the blocks..tt could have explained the presence of the shades...Besides sunlight, im oso guessing site survey could have studied the wind direction or sth like tt these shades could be used for preventing rain into the units? juz some wild guesses...