The human eye has about six million cones that are sensitive to green, red or blue.
She was stranded there after the wedding, when high winds prevented her from returning to her college on the island of North Uist, in the Outer Hebrides.
The one thing scientists could agree on was that this is a very unusual illusion.
Celebrity couples were torn asunder by the controversy you saw black and blue. People who see the dress one way do not eventually begin to see it the other way, as is common with many optical illusions. Unless, of course, you happened to be with someone who saw white and gold when.