 "turn on 522,730 through 968,950\n" +
 "turn off 102,229 through 674,529"
 
-var lights: [Int] = Array(count: 1000*1000, repeatedValue: 0)
-
-enum Action {
+private var lights: [Int] = Array(count: 1000*1000, repeatedValue: 0)
+private var brightness: [Int] = Array(count: 1000*1000, repeatedValue: 0)
+
+private enum Action {
     case None
     case TurnOn
     case TurnOff
     case Toggle
 }
 
-struct Instruction {
+private struct Instruction {
     let startPoint: CGPoint
     let endPoint: CGPoint
     let action: Action

    switch action {
    case .TurnOn:
        lights[index] = 1
    case .TurnOff:
        lights[index] = 0
    case .Toggle:
        lights[index] = (lights[index] + 1) % 2
    case .None:
        print("Reached .None case")
    }

    }
}

private func sumElements(source: [Int]) -> Int {
    //"+" is short for "$0 + $1"
    return source.reduce(0, combine: +)
}

public func numberOfLitLights() -> Int {
