Curiosity is always at the heart of every Baby Einstein product.  As a result, my goal is to encourage baby's curiosity about the world around them in a fun way.  These activity balls fit achieved that goal very well.  Each of the different balls contained a unique play feature that kept baby intrigued and entertained.  It also ended up being a pretty great and clever design when in the package because the balls created the iconic caterpillar's different body segments.  This product is still a huge hit.