think the flicker rate, level of color (or lack of) and the direction of its spin - PLUS - monitor and graphics card issues.... They all add up to a very disturbing graphic. I already spoke to someone in here about their epilepsy problems being spiked because of that particular graphic, in the Test server before it even went live.
The moment I saw it, I started to get a severe headache - so bad that I wondered if I wasn't growing a tumor or having a huge migrane.
The nausea begins if you keep looking at the darn thing. Especially if there are more than one on screen at the same time, that's so ... queasy...