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

Imagine a wheeled contrivance somewhat akin to a horse-drawn carriage, but much smaller and propelled by the rider''s own limbs rather than by beasts. This device, known as a "bicycle," has two circular frames fitted with thin bands of material which roll upon the ground as the rider moves the pedals with their feet.The rider, wearing a protective shell atop their head and garments resembling armor for safeguarding themselves, steers this curious mechanical steed through what is known as a city—a dense accumulation of dwellings and thoroughfares, much larger and busier than the towns you are familiar with. This particular rider also carries several bags and parcels, strapped securely to the frame of the bicycle, indicating that they might be a messenger or a trader, transporting goods from one location to another.Moreover, beside this paved pathway, there stands a tall post bearing what appears to be signs providing guidance or instruction, although in a manner much different than the heralds or town criers you would recognize. These signs include circles with mysterious symbols or arrows depicted within, intended to impart directives to travelers upon their way.Floating around the rider are also smaller, flat objects, perhaps symbolic representations of the tasks and responsibilities this messenger might be handling during their travels through such a bustling urban environment.