A different sort of tire swing (both seat and straps of recycled tire), and its wear patinas. An indefinite (self-propelled) ride will set you back one kuai (US $0.16). In isolation this business model might not work when one kuai will often get you a dumpling or two for comparison, but when placed next to the open air billiard hall the equation begins to make sense for parents seeking reprieve but still wanting their charge in eyesight.