An alternative to chlorine pools, the BioTop Natural Pools use plants to keep water clean and clear. Wikipedia has some more info on natural swimming pools as well. These could make a great addition to a permaculture design site.
This is actually a cool option for the stairways. The main stairway could have art this way up, as opposed to pictures.photo gallery up stairs, neat and organized. From the article Joanne Hudson’s Beach House in Philadelphia Magazine