This Scrippy uses 3 square graphics, entered as scrolling backgrounds, inserted into a positioned container.
To create this one, I first inserted a positioned container the same size as my graphics, 255 x 255. Next I inserted 3 backgrounds, setting the first to scroll down and to the right, the second to the right, and the third up and to the right.
In the Advanced Options section of the first background, the horizontal and vertical spacing is set at 2 times the graphic width. 255 x 2 = 510. Leave the horizontal and vertical starts set at zero.
For the second background, set the horizontal spacing at 2 times the graphic width and the vertical spacing at zero. Then set the horizontal start to equal the graphic width, using a minus sign to move it to the left. Leave the vertical start at zero.
Finally for the last background, set both the horizontal and vertical spacing at 2 times the graphic width. Then set the horizontal start at 2 times the graphic width using a minus sign . Then set the vertical start at 2 times the graphic width.
Make sure your scroll speed is the same for all the backgrounds.
You'll notice that I have a separate container for my frame because I wanted it to be outside the original container. So I sized this container to be 16 pixels larger than the original container, allowing for an 8 pixel frame.