Over a plywood surface I glued at every corner a column of cork "stones" that will anchored a melt of white glue and acuarium stones. these mas will be expanded rolling over it a kitchen wooden roll,for avoiding the stones stick in the wood roll you must trow talcum podwer over the melt.
When this is dry you must reduce the most prominent stones with a lime. last operation is a layer of spackle over entire wall , that must be retired with a sponge.the spackle only remains in the deep , among the stones.
