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

This image shows a fantastical carriage, unlike anything from your era. Picture a large, self-moving cart without horses, crafted from metal and other materials unknown to you. This cart has a sizeable cylindrical container mounted on its back, which likely holds some form of liquid or substance important for its mysterious function. The front part of the carriage has a cover that protects a brightly shining orb, which might be considered a lantern of sorts, guiding its path without the need for fire or oil. It moves on circular discs that rotate, propelling it forward across the ground, kicking up dust and stones as it speeds along an unseen road. Additionally, there are visible indications of motion or speed expressed through lines trailing from the rear of the vehicle. This mechanical contrivance represents an advanced form of transport and function, embodying skills and crafts far beyond your time’s capabilities.