Can you see the letter that is made out of the red dots when you combine both of these pictures?
It's apparently hard for most people, almost impossible even (though not for this author who just discovered they have a photographic memory).
This purportedly difficult challenge is just one of the trials in a quiz which aims to find out whether you have a photographic memory.
The real term for people who can recall images after brief exposure is called "eidetic memory". Actual "photographic memory" has never been found to exist, with some cognitive scientists calling it a myth.
People on the autism spectrum will often exhibit a strong aptitude for memory.
Of the many basic questions, which surprisingly huge number of people struggle with, are memory tests with white squares and grids and features of a painting.
According to the creator only 1% of the population will successfully answer the questions correctly.
Are you in the top one per cent? Find out here.
App users tap here.