If you want to encourage your baby's ability to recognize objects -I think that wallpaper in a larger scale pattern is the best choice.
Obviously primary colors are best for young children - the pastels are best used for "sleeping" only.
If you want to give your child a learning advantage - then choose bright colors - be sure to include red. By combining both primary and secondary colors, the scheme will last through to kindergarten age.
Choose a variety of nice shapes - remember baby can only see 8" - 15" in distance. Use a large-scale pattern near the crib, such as one of the wonderful new large vertical borders.
Another option is to use a horizontal border - if you place it near the crib, the baby will have something to look at when awake - giving mommy a little breathing time.
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