//var chx = this.getChildAt(0)
//var chy = this.getChildAt(1)
//var chz = this.getChildAt(2)
//this.numChildren
3
//this.addChild(chx)
//chy === this.getChildAt(0)
true
//chz === this.getChildAt(1)
true
//chx === this.getChildAt(2)
true
//this.numChildren
3
//this.addChild(chy)
//chz === this.getChildAt(0)
true
//chx === this.getChildAt(1)
true
//chy === this.getChildAt(2)
true
//this.numChildren
3
//this.addChild(chz)
//chx === this.getChildAt(0)
true
//chy === this.getChildAt(1)
true
//chz === this.getChildAt(2)
true
//this.numChildren
3
