The progress in this week.
With white glue, the thin plywood base was stuck onto the polystyrene foam board curved the wiring space and landform. Another plywood board was attached to the bottom of the polystyrene to make light and solid construction.
Sleepers cut out from styrene sheet were glued between the PC ties with proper interval. Simple wooden bridge was made of basswood. Side wall of the hollow is made of natural substance from the backyard ground.
I used paper clay to form the ground surface covering the gaps between the plywood and polystyrene. I prefer paper clay than plaster because it is more flexible to form a smooth and fine shape easily.
Finally the surface of the clay was covered with a soaked tissue paper to represent a course wrinkle of the ground.