VIX Term Roll Oscillator

My implementtion of VIX term roll Oscillator according to the articles below

seekingalpha.com/article/1439801-vix-contango-oscillator-profitable-observations?page=2
vixcontango.wordpress.com/2015/04/27/introduction-to-vix-contango-oscillatorvco-and-vix-term-roll-oscillator-vro/

Hope it helps!

Daniel