Adding an enemy and collision detection

Create a new file called Enemy and, similar to how we created the Hero class, we will pass the GameSCNScene in it:

import SceneKit

class Enemy: SCNNode{
    
    var _currentScene: GameSCNScene!
    
    init(currentScene: GameSCNScene) {
        
        super.init()
        self.create(currentScene: currentScene)
        
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    
    func create(currentScene: GameSCNScene){
        
        print("spawn enemy")
        
        self._currentScene = currentScene
        
        let geo = SCNBox(width: 4.0, height: 4.0, length: 4.0, chamferRadius: 0.0)
        geo.firstMaterial?.diffuse.contents = UIColor.yellow
        
        self.geometry = geo
       
        self.position = SCNVector3Make(0, 20.0 , 60.0)
        self.physicsBody = SCNPhysicsBody.kinematic()
        self.name = "enemy"
  ...