theres a dispenser using bonemeal on a moss block, and when this moss block expends , an observer sends a signal to trapdoors filled with water to release it and clean the area from any moss carpets or saplings, with will go in a hopper leading into composters, after this, the stone generator will produce stone that will be pushed by pistons, and at the end of the line there is obsidian that stops the moss blocks from moving, so it destroys itself as the pistons push the stone, when a stone block goes above the observer , the observer will send a signal to the dispenser to release bonemeal, which will trigger the observer into making trapdoors open etc...
