convenience init(imageNamed name: String) // Create an SKSpriteNode from a named image in the assets catalogue
var position: CGPoint // SKNode property, inherited by SKSpriteNode. The position of the node in the parents co-ordinate system.
func addChild(_ node: SKNode) // SKNode method, inherited by SKScene. Used to add an SKSpriteNode to the scene (also used to add SKNodes to other SKNodes).