The riddle in the White and Gray Visa Gift Card is in the number of shades of gray the human eye can discern. A quick look around the Internet will leave you scratching your head and deciding this matter itself is neither black nor white. It is fraught with subtleties and, yes, shades of gray. Some experts say human eyes can only see about 30 variations, while others go as high as 500! Of course, you can give White and Gray Visa Gift Cards because you like its soft visual appeal. But they also are a great vehicle to make a more or less strong statement of support for ambiguity.