since the placement of the lighter fabric of indicates where the sun is coming from, I would make all the "shadows" go the same direction...in number 3 you have four columns of window panes. the two right ones are made showing the light/sun coming from the upper left (since the lighter color is on the bottom) while the two right ones indicate that the sun is coming from the upper right (based on where the light/dark strips are). To get a more realistic look (if that's what you're going for) I'd move the darker strips in the two left columns on the left of the pane, just like you did on the two right hand columns. alternately you could change the dark strips on the two right hand columns. does that make sense?