They careened down the sidewalk and I quickly stepped out of their way. The first boy was hunched over the handlebars of a tiny green tricycle with an intense focus on pedaling as fast as he possibly could. The second boy sat atop a pink plastic cart being towed by the tricycle with a few yards of red twine, and he caught my eye while whooping and laughing and barely maintaining his seat on the thing as it tipped up onto two wheels, took the corner too fast, and disappeared down the block.