Rock on a Roll Planter
I've been playing around with something called Rock on a Roll. It is a vinyl sheet that looks and feels like rock - it is rough and scratchy. I learned as I went along and got better at shaping and gluing it. It was fun but a lot of work.
One of the things I did was to cover a cinder block with it to use as a planter. I cut it correctly to avoid gaps and seams showing, but then, in a moment of stupidity, glued it on wrong, so pretend you don't see the gaps on the edges. :-)
Although it is really for the pond forum, here is the floating island I made from the gray Rock on a Roll.