Assume nodeA is a child of nodeB. Changing the value of zRotation
for nodeB effectively rotates nodeA, but nodeA's position (since it's relative to nodeB) remains the same.
Now assume nodeA is removed from nodeB, but its position remains fixed in the screen. nodeC is added to nodeB and rotated.
How can you detect overlap between nodeC and nodeA? containsPoint
in SKNode, as described here, doesn't work since both nodeC and nodeA positions never change due to rotation.