What is in this image? Describe it as if you were explaining it to someone from the 15th century.

The image depicts a mechanical contraption that might best be described to someone from the 15th century as a sort of self-moving cart, though no horse or external force is visible for its propulsion. It has sturdy, circular bands that could be likened to millstones, though they are much thinner and serve as the cart’s bases, enabling it to traverse across the ground without animal aid.Atop the cart, there is a section reminiscent of a ladder, though fixed in nature, equipped with a series of steps aligned in such a fashion as to suggest that it could be raised towards the heavens. This ladder-like appendage is not made for climbing, but likely to reach high places for specific tasks.The body of the cart itself bears several compartments and features that might evade immediate understanding without context. It is constructed with a degree of robustness hinting at a function connected to labor or service of some societal need, possibly compartmentalized to hold various tools or essentials for its duties.Overall, the device would appear magical or fanciful, suggesting a blend of craftsmanship and unseen forces enabling its movement and utility.