reflections on windows are different than many other reflections because windows are inherently transparent. in general, when the light outside the house is stronger than the light inside the glass becomes reflective instead of transparent. from a distance it's not easy to see through the glass. and vice versa when the inside light is strong and it's dark outside the reflection is seen from inside the house and it's hard to see what is going on outdoors unless you stand very near the glass. viewing from outside the glass is transparent (hence folks often draw the curtains at night). the stronger the contrast. the greater the reflection.
but often the lights are on inside the house during the day. in that case there isn't much of a reflection either way. or as in this photo series, looking through the window from the outside one can see a window on the opposite wall. in these daytime shots there is a combination of reflections of windows from the neighboring yellow building behind me but also a window visible while looking through the house. because the light is coming through that window it makes the things inside that it lights up clearly visible
at the same time the upper window from the yellow house is reflected, we can clearly see out the window on the opposite wall and we can see the translucent white curtains, the table, chairs and a flower vase close to the window. the glass is only reflective while viewing the parts of the room that are relatively dark
standing closer to the window the amount of the yellow house being reflected increases considerably, even the cobblestone way between the houses can be seen. the yellow house has two floors. two upstairs windows and one downstairs window are reflected. at the same time the opposite window has become so much brighter causing that area to be overexposed. the table, chairs and vase are the same. it appears that the curtains have been drawn but nobody is inside, do either it is an illusion or there is a ghost attempting to get some privacy from nosy people like me. the ceiling and beam seem ghostly enough so you never know in these old houses from the 1700s
the curtains are open again but i never saw anybody in the house and i am positive nobody was there. the reddish shirt arm and the fingers in the lower right corner are all mine. i won't bore you with an explanation of the 'drawn curtains'. see if you can figure it out