HI,
Thanks for the question. This might be quite challenging for RailClone because it's necessary to fill a complex area with geometry that doesn't look as though it it tiles. If however, it's more like regular bricks that are surrounded by larger areas of concrete, then you might be able to do something like the attached file which uses the same style by raises it on the Z axis and rotates the array by a further 90 degrees. For more irregular bricks you could always pre-compose some stones shapes like in
this post I hope that helps, please let me know if I can do anything further,
Paul