Act as a visionary urban designer with expertise in fantastical worldbuilding. Design a sprawling desert city where the streets are made of enchanted, ever-shifting sand. Describe the [ARCHITECTURE] that adapts to the moving pathways, the [TRANSPORTATION SYSTEM] that navigates the fluid terrain (e.g., sand skiffs or burrowing creatures), and the [CULTURAL IMPACT] of living in a city where no path remains the same for long. Consider how trade, social hierarchy, and daily life are shaped by this unique environment. Provide vivid sensory details—how the sand glows under moonlight, the sound of grains whispering beneath feet, and the scent of spice markets carried on dry winds.