These stick-on wall decals from WallCandy are supposed to stimulate visual and cognitive development:
Appropriate visual stimulation is an important component of a child’s visual and cognitive development.
Images similar to those found in WallCandy Smarts have been scientifically demonstrated to capture a child’s attention and promote visual growth.
– Ophthalmologist Dr. Charles Barsam
From the website: Enhance your newborn & infants’ gross motor skill & eye sight development with our pediatrician and ophthalmologist approved 3 step nursery decoration program. Personalize with your own photos in our frames.
Apparently you start off with just the black and white checkers, trees, and bees. Then comes the red, blue, and yellow-colored variations. Lastly you add family photos. The whole set includes 50 movable and reusable decals, $24.99.