Water slides
Spiral slides
Open and enclosed spirals that share a tower — two distinct rides from one staircase and one pump room.
Spirals are the workhorses of a water park. They are the most flexible slides to route around an awkward plot, they can share a tower with other flumes, and at 7.5 kW each they are the cheapest tower slides to run.
The open and enclosed versions descend almost identically but feel completely different. Specifying both from one tower gives a park two attractions for barely more than the cost of one.