The following playground results in a timeline error "unrecognized selector sent to class..."
import SpriteKit
let node = SKShapeNode(circleOfRadius: 10)
Seems to work ok when platform is iOS. Running 10.9.3
It's because you're running it on an OS X version that's older than the API you're trying to use. The code you're using requires OS X 10.10, or iOS 8 and up.
The OS X 10.10 API Differences confirm that all of SKShapeNodes custom initializers have just been added in 10.10. Previously, all we could do with SKShapeNode, was initialize an instance, and then modify its path property.
来源：https://stackoverflow.com/questions/24127212/skshapenodecircleofradius-results-in-unrecognized-selector-sent-to-class-in