They can be
On July 10th, the science news blog Inside Science [30] published an article explaining the optical illusion, claiming that people who fail to see two different color bottles lacked "the peripheral color vision to reliably distinguish between the two shades." Additionally, the article contained an analysis of the RGB values in the image, which determined that the shoe's hue was slightly closer to the polish on the right (shown below)
Style: macd_68076 Collection: Mac Duggal Prom Fabric: Chiffon Details: Floral, Sleeveless, Printed, Ruched, Body cut out, Tiered, S back, Bare back, Floor length, Sweep train Length: Long Neckline: Deep V Neck Waistline: Natural Silhouette: A-line
Length Lying Flat: X-Small-45.5", Small-46", Medium-46.5", Large-47"
The dress has a flattering scoop neckline and delicate spaghetti straps that add a touch of sophistication