3 ms·

yes some people dont have to close their eyes.

• ironmagma 6y ago
  You can somewhat train it as well through getting better at drawing.
• Tor3 6y ago
  It makes no difference for me if I close my eyes or not. On the other hand the ball isn't as clear as a real image, most of the time, I see the black pentagons but if I try to count them I lose focus on the ones I'm not currently counting.