LBC Retaining Wall
The steps going up from the patio and the slight curving
I really like the look of Gabion Walls. They are using them a lot in Seattle. The wiring can be made onsite. I'm not sure of the cost vs. concrete You can also run a dripline at the top and movement converts the rock pile into an evaporate cooler (outside a/c) (this is according to the experts anyway) You can also use junky (but sturdy) material in the middle.
Extra seating but you would have to have some sort of a bridge for the drainage canal
Getting ahead of myself
Different...hadn't thought of this
more than just concrete