Innovations in architecture have shifted to hot outdoor designs that are supposed to be low maintenance and stylish. Marcus Hiles has seen the spike in demand for open-air spaces that are sustainable and also reduce expenses. Eco-friendly and conservation alternatives such as rainwater/graywater harvesting and permeable pavement are popular methods. Using a rooftop collection methodology, rainwater harvesting sends moisture from the air for storage in a well to be purified and reused on-site; graywater makes use of home wastewater and redirects it to toilets and non-drinking uses, decreasing the want for fresh water and saving resources on purification. A unique idea for environmentally minded construction, permeable paving, dates back to thousands of years to an era when people first constructed roads by putting stones in beds over the ground. The procedure allows the rain to pass through small openings between four layers of filtration (paving material, gravel, fabric, sand) before becoming absorbed by the earth beneath. Its positives include lowering runoff and pollution, controlling the flow of storm water to gutters and drains, replenishing local groundwater supplies and providing a skid resistant surface for walkways, patios and driveways; their various appealing patterns often incorporate crushed stone, brick, and recycled concrete.