In the picture, we know that there is depth and distance just by looking at it.


The distance and depth is noticeable right away with one eye alone.
Pictures from: https://www.google.com/search?q=monocular+cue+examples&source=lnms&tbm=isch&sa=X&ei=RM57UsLwGtSysAT_qoHQDg&ved=0CAcQ_AUoAQ&biw=1280&bih=907#facrc=_&imgdii=_&imgrc=OpJbN0OgH0E8RM%3A%3BAahAXMIrxjFE7M%3Bhttp%253A%
https://www.google.com/search?q=