What you see here citizens in general never see: portions of an actual depository platform. Locating a particular platform is the final stage of each unit's journey.
Units are constructed from many materials, some ancient, some so new as to be untested. Some are even created by assemblers, for they span the range from basic joiners of preset components to extremely talented and often obsessed designers and inventors of new materials, new circuits, access modes, screen presentation. And cracking, of course.
Commonly, materials are brightly colored polymers which are durable, smooth, adaptable. Pure metals have a solidity attractive to some, yet they are heavy and can be more easily damaged. Unless treated they are subject to oxidation and other environmental ravages.
Fundamental to each unit are access pressure points and data display areas. The access is 1 or more buttons, bars, lights, etc.
Units are powered in most cases by plasma directed through jets which permit precision, speed, adaptation, and hovering.
These are commonly used models and colors at present except for the central unit usually referred to as a messenger rather than as a comm unit. More will be said of this later.
Mediators are responsible for checking the depository for units directed to them. Those seeking mediated assistance but no specific mediator are taken up in rotation by the group or dispersed in any other manner agreeable to the group.
Mediators possess sensors and routers, usually subelements of a mediator's seal, which permit them to detect new arrivals from a distance and summon them or to direct units from the depository to their offices or dwellings without escort.
Upon arrival each negotiates a hover point and remains on alert sensing proximity and stacking of all other units on the platform. Each also has sensors tuned to the particular mediator for which it is intended.
Most materials at present are capable of changing hue directed by thermal or acid-base modifications whose sequencing and timing are programmed by the assembler or sender.
Alloys and composites correct these faults while preserving much that is pleasing about the metallic models. But they are also valued for their inherent qualities. Their properties allow for more individualized adornments and flexibility in joining.
Some units still employ electron or proton exchange stacks, magnetic field differentiation grades, acid-base flows, or electrolysis.
Early models utilized combustion and compressed oxidation schemes but these methods are presently discouraged.
View sample units for more detailed information.
Screens are 1 or many, in patterns or stacks, or supplant each other within a viewer which can also have many sizes and styles.
Units must meet common hazards and complexities of city streets. Some must also meet further challenges when their data loads are controversial or deemed valuable by traffickers wishing to capture and hold them for ransom.
If no mediator has been designated a unit must adeptly maneuver the delicate margins, making itself noticed without breaching aggression standards. Here is another reason a skilled assembler is advantageous.

Check the chatter: assemblers, senders, mediators