Yesterday, we learned that the researchers are working to create a 3D face reconstruction of the woman believed to be Mona Lisa, now there may be another connection to Da Vinci and the third dimension that doesn't require expensive technology or excavating graves.

Claus-Christian Carbon and Vera M. Hesslinger of eXPerimental Psychology in Germany believe Da Vinci painted the famous painting with an apprentice by his side who also painted the same woman, but from an adjacent perspective. They have layered the first and second painting (which sits in the Prado Museum) and found that they form an unintentional stereoscopic image.

Until 2012, the Prado Mona Lisa had been considered "unremarkable, just one of many anonymous copies." A Prado researcher examined the once blackened and varnished background of the painting with an infrared camera and found that it had the same landscape as the original. "The black paint has now been removed, and further imaging has revealed layers with the same changes and corrections made to the original. It appears that the two paintings may have been painted at the same time, in the same place, both artists tweaking the work in the same ways," writes Science News.

Through perspective calculations and data collected from the visual estimations of 32 people in a study, Carbon and Hesslinger recreated the scene using the minifigures below:

By tinting the layers, the researchers show how the effect that the images would have if they were viewed side-by-side (how today's 3D images work when the two images are placed slightly out of sync). In their full report, published in Perception, they writes that "whether this quality was actually created by intention or by accident can, of course, not be said for sure—but in the case of Leonardo, you never know."

Check out the eXPerimental Psychology website to learn more about this interesting research project.

[via Designboom]