Clone Multiple Patterns At Once?

[Drain]

I'm looking for a way to simulate the "multiple patterns at once" effect going on in the video below. I already have large tiled patterns for the cross hatched rock and the stone floor and they work great using the Clone Tool. 

The other thing I can't figure out (and GIMP might not have this ability) is how to setup a brush to create the squared off walls that's open on the trailing edge like in the video.





Thanks in advance for any help