Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)

“In anatomy, heterochromia refers to a difference in coloration, usually of the iris (but also of hair or skin). Although infrequently seen in humans, complete heterochromia is more frequently observed in other species, where it almost always involves one blue eye”. – Wikipedia (Photo by StooMathiesen)

A model presents a creation from the Jeremy Scott Spring/Summer 2015 collection during New York Fashion Week September 10, 2014. (Photo by Lucas Jackson/Reuters)

Jeremy Scott's spring 2019 collection is modeled during Fashion Week in New York, Thursday, September 6, 2018. (Photo by Kevin Hagen/AP Photo)

A couple walks across the Francis Scott Key Bridge as the setting sun lights up the clouds in Washington, Friday, October 30, 2020. (Photo by J. David Ake/AP Photo)

A model is filmed backstage before the Jeremy Scott Fall/Winter 2015 collection presentation at New York Fashion Week February 18, 2015. (Photo by Andrew Kelly/Reuters)

Gun enthusiasts look over Smith & Wesson pistols at the NRA Annual Meetings & Exhibits on May 21, 2016 in Louisville, Kentucky. About 80,000 visitors are expected to attend the three-day event. (Photo by Scott Olson/Getty Images)

A mural depicting Prime Minister Scott Morrison wearing an unbuttoned Hawaiian shirt, orange lei and Santa Claus hat while holding a cocktail by artist Scott Marsh is seen on a wall in Sydney, Wednesday, December 25, 2019. Morrison was under pressure since taking a much criticized family vacation to Hawaii during the wildfire crisis.(Photo by Steven Saphore/AAP Images via AP Photo)