I used seldf hardening clay to make the bark of the tree. I have a lot left and as i already had a package drying slowly away because the package was not closed airtight i prefer using this clay to build a wall programmed anyway. It is meant to put behind the houseson the edge of the parking. I rolled it out 1 cm thick between two pieces of wood and simply scribed the pattern in while workable. I did this a few times, not knowing exactly the curing point and slowly getting to this look. This are slate stones put one on top of the other without mortar

I will cut the wall lenthwise in two pieces to get roughly a meter of it.