Xcode playground starter code to experiment with SpriteKit.

SpriteKitPlaygroundStarter.swift

import PlaygroundSupport
import SpriteKit

// Set up scene:

let size = CGSize(width: 480, height: 320)
let scene = SKScene(size: size)
scene.physicsBody = SKPhysicsBody(edgeLoopFrom: scene.frame)
scene.physicsWorld.gravity = CGVector.zero // Enabled later

let sceneView = SKView(frame: CGRect(origin: CGPoint.zero, size: size))
sceneView.showsFPS = true
sceneView.showsNodeCount = true
sceneView.showsPhysics = true
sceneView.presentScene(scene)
PlaygroundPage.current.liveView = sceneView


// Code here...


// Briefly pause before enabling gravity so that we don't miss some action while the playground starts execution.
DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
    scene.physicsWorld.gravity = CGVector(dx: 0, dy: -9.8)
}