Ya I think you got it.   I just dabbled with swift and wrote my experiences here:   <a href="http:&#x2F;&#x2F;psgraphics.blogspot.com&#x2F;2014&#x2F;09&#x2F;inheritance-for-swift-ray-tracer.html?m=1" rel="nofollow">http:&#x2F;&#x2F;psgraphics.blogspot.com&#x2F;2014&#x2F;09&#x2F;inheritance-for-swift...</a>