Reversible Infant-Stim Crib Bumper Panel & Book in One! by Genius Baby Toys Inc. Baby’s Double-Sided First Book was designed to encourage visual stimulation and tummy-time play for head-lifting exercise.One side is for birth to 3 months -- with high-contrast black, white & red illustrations for early visual stimulation -- the other for 3 to 6 months with brightly colored, more complex raised 3-D figures and activities, to entice baby to tummy-time play.Your baby should be placed on his or her tummy for tummy-time play when awake and supervised.Tummy-time helps develop neck and shoulder muscles.Genius Baby Toys develops toys such as the Double-Sided First Book, for providing appropriate stimulation to encourage tummy-time play.