You DON'T need to close one eye, it can help, but if you hold a light source behind you , and don't cast any deceiving shadows on the dragon, the illusion WILL WORK.
Basically, what ruins it is that our eye figures out theres a discrepancy between the shadow were seeing and the shadow that should be there.
Basically, what ruins it is that our eye figures out theres a discrepancy between the shadow were seeing and the shadow that should be there.
Try it!