Create your window frame as 4 separate props - one for each side. Every side should be a vertical matrix, 1 pixel wide. You will need to rotate 3 of the sides. In preview design, make sure there is a blue pixel in every corner - this ensures that the pixels are oriented in the correct order. Finally create a group with all 4 sides, so you can still use bar and spiral effects to go around the entire window frame. When doing your meteor effect - note that 1 side will be oriented from top-to-bottom and the other will be bottom-to-top. This means that in order for the meteors to go the same direction, the meteor effect direction will be up on one side and down on the other. This will take some fiddling to get everything oriented correctly, but it can work, and offers more flexibility when sequencing effects.