The rock face forms the scenic break feature at one end of the layout. The base for the plaster rock mouldings were made from polystyrene cut to shape and glued down with PVA. Making the mouldings is very straightforward and they are easily cut and filed to shape or size. Once moulded they are wetted and then matched with a strip of plaster cloth and fixed in place. It looks pretty unimpressive at this point and the look on my wife's face when she saw at this point proved the point to me. However, over the next couple of days after drying out, painting and then adding foliage and scatter material this underwhelming white lump in the corner of the layout metamorphoses into something quite realistic and I have to say spectacularly impressive.
If anyone is unsure of this product and whether they have the skills to achieve such realistic results then my advice is to put aside any such doubts and get stuck in. At around £11 for a learner kit it is fantastic value for money.