Swift Playgrounds Analog Clock Example.

clock.swift

import SpriteKit
import PlaygroundSupport

class Scene: SKScene {
    var hands: [String: SKShapeNode] = [:]
    
    override func didMove(to view: SKView) {
        let center = CGPoint(x: frame.midX, y: frame.midY)
        let radius = CGFloat(450)
        let face = SKShapeNode(circleOfRadius: radius)
        face.position = center
        face.lineWidth = 10
        face.strokeColor = #colorLiteral(red: 0.8039215803146362, green: 0.8039215803146362, blue: 0.8039215803146362, alpha: 1.0)
        face.fillColor = #colorLiteral(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)
        addChild(face)
        for i in 1 ... 12 {
            let label = SKLabelNode()
            label.text = String(i)
            label.fontSize = 100
            label.fontColor = #colorLiteral(red: 0.0, green: 0.0, blue: 0.0, alpha: 1.0)
            let a = 2 * CGFloat.pi * CGFloat(i) / CGFloat(12)
            let b = CGFloat(380)
            let c = label.frame.height / 2
            let x = sin(a) * b
            let y = cos(a) * b - c
            label.position = CGPoint(x: x, y: y)
            face.addChild(label)
        }
        let attrs: [(String, CGFloat, CGFloat, UIColor)] = [
            ("m", 350, 8, #colorLiteral(red: 0.0, green: 0.0, blue: 0.0, alpha: 1.0)),
            ("h", 280, 12, #colorLiteral(red: 0.0, green: 0.0, blue: 0.0, alpha: 1.0)),
            ("s", 350, 4, #colorLiteral(red: 0.8078431487083435, green: 0.027450980618596077, blue: 0.3333333432674408, alpha: 1.0))
        ]
        for (name, length, width, color) in attrs {
            let p = CGMutablePath()
            p.move(to: CGPoint(x: 0, y: length))
            p.addLine(to: CGPoint(x: 0, y: 0))
            let s = SKShapeNode(path: p)
            s.lineWidth = width
            s.strokeColor = color
            s.lineCap = .round
            hands[name] = s
            face.addChild(s)
        }
    }
    
    override func update(_ currentTime: TimeInterval) {
        let now = Date()
        let cal = Calendar.current
        let hh = CGFloat(cal.component(.hour, from: now))
        let mm = CGFloat(cal.component(.minute, from: now))
        let ss = CGFloat(cal.component(.second, from: now))
        
        let tick = -2 * CGFloat.pi / 60
        let s = tick * ss
        let m = tick * mm
        
        let tock = -2 * CGFloat.pi / 12
        let h = tock * (hh + mm / 60)
        
        hands["s"]?.zRotation = s
        hands["m"]?.zRotation = m
        hands["h"]?.zRotation = h
    }
}

class ViewController: UIViewController {
    override func viewDidLoad() {
        let r = CGRect(x: 0, y: 0, width: 1000, height: 1000)
        let s = Scene(size: r.size)
        s.scaleMode = .aspectFit
        let v = SKView(frame: r)
        v.showsDrawCount = true
        v.showsNodeCount = true
        v.showsFPS = true
        v.presentScene(s)
        view = v
    }
}

PlaygroundPage.current.liveView = ViewController()
PlaygroundPage.current.wantsFullScreenLiveView = true