protocol Run {
  var canRun: Bool { get }
  var speedRun: Int { get }
}

extension Run {
  var canRun: Bool { return true }
  var speedRun: Int { return 100 }
}

protocol Walk {
  var canWalk: Bool { get }
  var speedWalk: Int { get }
}

extension Walk {
  var canWalk: Bool { return true }
  var speedWalk: Int { return 50 }
}

struct Mark: Run, Walk {}

// override
struct Jack : Run, Walk {
  var speedRun: Int { return 200 }
  var speedWalk: Int { return 100 }
}


Mark().speedRun
Mark().speedWalk
Mark().canRun
Mark().canWalk

Jack().speedRun
Jack().speedWalk
Jack().canRun
Jack().canWalk