There's a picture of tiger: http://www.solarnavigator.net/animal_kingdom/animal_images/Tiger_panthera_tigris_tigris_Bengal.jpg How many stripes it has?

Turns out the number of stripes is not even well defined. Let alone can be told right away in an instant. Obviously one coming up with tiger example doesn't have good enough mental imagery to see the flaw without looking at a photo of a tiger.