Macbook Pro Retina 15" (mid 2012) screen is glitching in specific situations The display of my macbook is glitching as you can see in image below. However this is happening only if I'm trying to do some on graphics heavy tasks, just like opening big Rhinoceros project. The second occasion is when I wake up computer (from Sleep mode) and it was NOT pluged in. This glitching stops after a while, but it is at least disconcerting.

Does anyone have any advice?
Very likely your MacBook has a defective GPU. You are lucky however, since there is a recall for your specific model. 

Check your eligibility here and contact AppleCare.