At least six. Maybe more. Obsessively, too, as it was my grand challenge problem to solve all of it with a holistic solution. Got pretty close conceptually from

At least six. Maybe more. Obsessively, too, as it was my grand challenge problem to solve all of it with a holistic solution. Got pretty close conceptually from a number of angles. End result was software or especially hardware options will need to be developed by specialists at significant cost. Now, I still collect the science while looking at marketing or development strategies a bit more.