SpriteKit joint physics changing physics body - xcode

Question

I am working with the joint method in spritekit, but once I join two sprites it seems to change the physics bodies. I have two rectangles joined at a corner and when they fold, I would expect the blue rectangle to sit on top of the white triangle, but this is the result. How do I maintain their physics bodies, so they don't overlap?
import SpriteKit
class GameScene: SKScene {
let character = SKSpriteNode(color: SKColor.whiteColor(), size: CGSizeMake(150, 30))
let character2 = SKSpriteNode(color: SKColor.blueColor(), size: CGSizeMake(150, 30))
let character3 = SKSpriteNode(color: SKColor.greenColor(), size: CGSizeMake(50, 300))
let screenSize: CGRect = UIScreen.mainScreen().bounds
override func didMoveToView(view: SKView) {
// let scene = GameScene(size: SKView.frame)
let borderBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
borderBody.friction = 5
self.physicsBody = borderBody
self.physicsWorld.gravity = CGVectorMake(0.0, -1.0)
character.position = CGPointMake(550, 400)
character2.position = CGPointMake(400, 400)
character3.position = CGPointMake(400, 100)
character.physicsBody = SKPhysicsBody(rectangleOfSize: character.size)
character2.physicsBody = SKPhysicsBody(rectangleOfSize: character2.size)
character3.physicsBody = SKPhysicsBody(rectangleOfSize: character3.size)
self.character.physicsBody!.dynamic = true
self.character2.physicsBody!.dynamic = true
self.character3.physicsBody!.dynamic = true
self.addChild(character)
self.addChild(character2)
self.addChild(character3)
var myJoint = SKPhysicsJointPin.jointWithBodyA(character2.physicsBody, bodyB: character.physicsBody, anchor: CGPoint(x: CGRectGetMaxX(self.character2.frame), y: CGRectGetMinY(self.character.frame)))
self.physicsWorld.addJoint(myJoint)
var myJoint2 = SKPhysicsJointPin.jointWithBodyA(character2.physicsBody, bodyB: character.physicsBody, anchor: CGPoint(x: CGRectGetMaxX(self.character2.frame), y: CGRectGetMaxY(self.character.frame)))
//self.physicsWorld.addJoint(myJoint2)
}