Megan Walsh watched her 2-year-old son size up the hammock in front of him. The woven seat, fit for a toddler but not much bigger, hung right at his eye level. With a little help from his mother, he dove in and nestled safely inside. His feet, sporting slightly worn camo socks, peeked out. Walsh smiled. Comfortable isn’t usually how she feels at play places. But We Rock the Spectrum in .