     }
 }
 
-fileprivate extension UIView.Axis {
+fileprivate extension UILayoutConstraintAxis {
 
     var initial: Character {
         switch self {
-        case .x: return "H"
-        case .y: return "V"
+        case .horizontal: return "H"
+        case .vertical: return "V"
         }
     }
 
-    var reversed: UIView.Axis {
+    var opposite: UILayoutConstraintAxis {
         switch self {
-        case .x: return .y
-        case .y: return .x
+        case .horizontal: return .vertical
+        case .vertical: return .horizontal
         }
     }
 }


public extension UIView {

    enum Axis { case x, y }

    func constraint(_ subviews: [UIView], equallyAlong axis: Axis) {
        var axisFormat: String = "\(axis.initial):|"
        var dictionaryViews: [String: UIView] = [:]
        var oppositeFormat: [String] = []

            let key = "subview\(index)"
            dictionaryViews[key] = subview

            oppositeFormat.append("\(axis.opposite.initial):|[\(key)]|")
            axisFormat += "[" + key + (index == 0 ? "" : "(==subview0)") + "]"
        }

