creates a zig zag view border inside of a swift playground. Create a new playground, and paste in the following code:

zigZagViewBorderPlayground.swift

import UIKit
import PlaygroundSupport
let uiview = UIView(frame: CGRect(x: 0, y: 0, width: 300, height: 300))
func pathZigZagForView(givenView: UIView) ->UIBezierPath {
    let width = givenView.frame.size.width
    let height = givenView.frame.size.height
    
    let givenFrame = givenView.frame
    let zigZagWidth = CGFloat(7)
    let zigZagHeight = CGFloat(5)
    var yInitial = height-zigZagHeight
    
    let zigZagPath = UIBezierPath(rect: givenFrame.insetBy(dx: 5, dy: 5))
    zigZagPath.move(to: CGPoint(x:0, y:0))
    zigZagPath.addLine(to: CGPoint(x:0, y:yInitial))
    
    var slope = -1
    var x = CGFloat(0)
    var i = 0
    while x < width {
        x = zigZagWidth * CGFloat(i)
        let p = zigZagHeight * CGFloat(slope) - 5
        let y = yInitial + p
        let point = CGPoint(x: x, y: y)
        zigZagPath.addLine(to: point)
        slope = slope*(-1)
        i += 1
    }
    
    zigZagPath.addLine(to: CGPoint(x:width,y: 0))
    
    yInitial = 0 + zigZagHeight
    x = CGFloat(width)
    i = 0
    while x > 0 {
        x = width - (zigZagWidth * CGFloat(i))
        let p = zigZagHeight * CGFloat(slope) + 5
        let y = yInitial + p
        let point = CGPoint(x: x, y: y)
        zigZagPath.addLine(to: point)
        slope = slope*(-1)
        i += 1
    }
    zigZagPath.close()
    return zigZagPath
}

func applyZigZagEffect(givenView: UIView) {
    let shapeLayer = CAShapeLayer(layer: givenView.layer)
    givenView.backgroundColor = UIColor.clear
    shapeLayer.path = pathZigZagForView(givenView: givenView).cgPath
    shapeLayer.frame = givenView.bounds
    shapeLayer.fillColor = UIColor.red.cgColor
    shapeLayer.masksToBounds = true
    shapeLayer.shadowOpacity = 1
    shapeLayer.shadowColor = UIColor.black.cgColor
    shapeLayer.shadowOffset = CGSize(width: 0, height: 0)
    shapeLayer.shadowRadius = 3
    
    givenView.layer.addSublayer(shapeLayer)
}
applyZigZagEffect(givenView: uiview)
PlaygroundPage.current.liveView = uiview