There are numerous variations on “spot the difference.” Many different painters, illustrators, and photographers have taken up the challenge of subtly altering an image. It’s similar to meeting identical twins. On the surface,

They appear to be the same, yet the closer you look — and the sharper your eyes — the more subtle the distinctions become. How quickly can you spot the differences in these portraits? Set a stopwatch and see if you can beat your previous best time…

And finally, in 1806, American painter Joshua Johnson created “Grace Allison McCurdy (Mrs. Hugh McCurdy) and Her Daughters, Mary Jane and Letitia Grace,” named after those depicted.