Here is a link to the topic on the QB. I tried hunting for a pattern and could only find a link through delphi forums which you have to join. The link is also provided on post #27 of the below linked thread. I did not sign up for the forum and subsequent posts on the topic indicated it was full of popup adds and several gave up. It looks to me like the side window panes need to be cut into rectangles and diamond shapes to get the illusion and only the middle panes are cut as squares. The angle is hard to tell from the picture and it is possible you may need two of the same panel in order to get the cuts you would need but not positive.
Bay Attic Window with a panel.