Levelling blocks for camper on driveway with 2 degree grade

JimK-NY wrote:
Also mix a little fine sand into varnish or another finish so they do not slip when stacked.

I put tight-fitting carriage bolts in that stick down into looser-fitting holes on the layer below. As you can see from the crack, I could use the threaded rod idea. Though honestly I’ve only split a couple blocks in 16 years of use.