Creating a background sprite node - swift

Question

I'm trying to create an endless scroller game and I'm trying to create two backgrounds.
I have a background class like so,
class BackgroundMG1: SKNode {
let background: SKSpriteNode
let size: CGSize
init(size: CGSize) {
self.size = size
let hue = CGFloat((arc4random() % 1000) / 1000)
let randomColor = UIColor(hue: hue, saturation: 1, brightness: 1, alpha: 1)
self.background = SKSpriteNode(color: randomColor, size: size)
super.init()
setup()
}
func setup() {
background.position.x = 0
background.position.y = 0
addChild(background)
}
}
I'm going to be populating my background with other objects so I needed it to be a class and not just a static image.
I have my game scene like so,
class AntarcticaMiniGame1: SKScene {
var player: SKSpriteNode!
var backgrounds: [BackgroundMG1]!
override func didMove(to view: SKView) {
setup()
}
func setup(){
// Initializers
player = Player()
// Positions
player.position.x = 0
player.position.y = 0
player.zPosition = 1
// Set up backgrounds
backgrounds = [BackgroundMG1]()
for i in 0..<2 {
let background = BackgroundMG1(size: size)
background.position.x = CGFloat(i) * size.width
background.position.y = 0
backgrounds.append(background)
addChild(background)
}
// Add to scene
addChild(player)
}
override func update(_ currentTime: TimeInterval) {
player.physicsBody!.applyForce(CGVector(dx: 25, dy:0))
}
}
You can also assume that I have a ground and camera object set up. I had to omit that code because it's not relevant to this question. The player stays on the ground and the camera follows the player.
Right now, when I load the game, the player object is moving to the right as expected. I see one background, but the second one doesn't show up.
I feel like I'm making some mistakes with the positioning. I'm not a 100% how the coordinate system works in Swift.
Edit: My scene is connected to a .sks file which is totally empty right now. The game is in landscape orientation.