Draw the Golden Spiral in Swift

Golden

// Playground - noun: a place where people can play

import UIKit

let 𝜋 = M_PI
let ɸ = (1 + sqrt(5))/2

func drawTiles(tileCount: Int, height: Double, context: CGContext) {
    let red = CGFloat(arc4random_uniform(100)) / 100.0
    let green = CGFloat(arc4random_uniform(100)) / 100.0
    let blue = CGFloat(arc4random_uniform(100)) / 100.0

    CGContextSetRGBFillColor(context, red, green, blue, 1.0)
    CGContextFillRect(context, CGRectMake(0, 0, height, height))
    
    let arc = UIBezierPath();
    let center = CGPointMake(height, height)
    arc.addArcWithCenter(center,
        radius: height,
        startAngle: -𝜋,
        endAngle: -𝜋/2 ,
        clockwise: true)
    arc.stroke()
    
    let scale = 1 / ɸ
    if (tileCount > 0){
        CGContextRotateCTM(context, 𝜋/2 )
        CGContextTranslateCTM (context, 0 , -height*(1+scale));
        CGContextScaleCTM(context, scale, scale)
        drawTiles( (tileCount-1), height, context)
    }
}

func drawGoldenSpiral(tileCount: Int, height: Double) -> UIImage {
    
    UIGraphicsBeginImageContext(CGSize(width: height * ɸ, height: height))
    
    drawTiles(tileCount, height, UIGraphicsGetCurrentContext())
    
    let spiralImage = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return spiralImage
}

let spiralImage = drawGoldenSpiral(12, 500.0)