parallax errorTry pointing one finger at an object that’s a few meters away from you, say a wall clock. Then cover one eye at a time. Which one focused exactly? There should only be one. If you used your finger on your right hand, the eye that gives the right focus should be the left one (that means, the right eye is shut) and vice versa
What explains this? its something called parallax error – an optical illusion of some sort.
My grad school prof who seems to know a little of so many things told us this including the fact that employment at IRRI (dedicated to irrigation research, among other things) pays well (surprising for a government agency).