Scintilla - Life in Ambulon: Ambulon's constant movement means that even the most solid buildings are in danger of being shaken off the mobile city's structure. This in turn means that the city's wealthiest and most important districts are located in the places where they are least likely to be destroyed, especially along the city-machine's "Spine."The Spine's buildings are rarely as big as on hive city spires, since space is at such a premium on Ambulon's carapace, nor are they as tall, as they have to endure the constant swaying of the city-machine's slow, rolling gait. The style of the Spine sees elegance and even minimalism preferred to the grotesquely grandiose ornamentation common in the great hives. The nobles of Hive Sibellus, in particular, consider Ambulon to be a cultural backwater, whose nobles neglect the proper pursuits of beautifying their city and venerating their dead.Ambulon's equivalent of the middle hivers are the hundreds of thousands of workers who inhabit tenement blocks piled up on the vast, shield-shaped back of the city-machine. These tenements are plagued by city-quakes caused by the city's constant movement, and are all shored up and extensively repaired after past collapses. Few streets run between Ambulon's buildings since there is not enough space for them, so the middle classes tramp to work across the roofs of the tenements, or even through each others' homes.Almost all the middle classers are engaged in harvesting or refining the raw materials that Ambulon gathers from the igneous wastes of Scintilla. The "head" of the city is equipped with immense drills that can be lowered into the rock, and when the mobile city strikes oil, thousands of flexible pipelines are lowered from the edge of the city to pipe up as much of the oil as possible as the city-machine passes by.Working on these pipelines, which are controlled by webs of chains like the strings of vast puppets, is very dangerous and requires a hardy breed of men and women with no fear of heights. Ambulon's many refineries process this oil into promethium fuel, some of which is piped back into the city-machine, while most forms the majority of the city's tithe contribution, to be delivered to Hive Sibellus and Gunmetal City. Other citizens sift through the rock thrown up by the drilling to pick out precious stones, which are then worked into industrial components, or cut for jewellery in workshops inhabited by generations of gemcutters (considered a hereditary occupation on Ambulon).Ambulon's lack of space means that every citizen must justify their presence there and unemployment is illegal. Each household in the middle city is tied to a particular refinery, workshop or other industry, and its members may not work anywhere else. It is vitally important for every middle citizen to be properly recorded in the "Rolls of Justification" which each place of industry maintains, because if they cannot prove to the authorities of the Spine that they are permitted to fulfil the role in which they work, they are banished to the mobile city's "Underbelly."Ambulon's "underhive" clings precariously to the belly of the city-machine. It is known by a variety of colourful names such as the Underbelly, "the Guts," "the Vitals" or even the "Hivegroin." Clusters of hovels blister down from the city-machine like warts, connected by makeshift catwalks and rope bridges. Many thousands of people live only a footstep away from plummeting to their deaths towards the rocky ground that constantly grinds by hundreds of metres below.Underbelly settlements are often scraped off the city-machine's underside by ridges or peaks that the city-machine walks over, or are simply shaken off by the city's movement. Life is short and very difficult here, and the underhivers or "Gutscum" live off the detritus of the carapace above, constructing scoops to catch the effluent and waste thrown off the edge of the city, or they form bandit gangs to prey on the citizens who work near the edge of the city-machine's back.One prominent feature of the Underbelly is the cages hung from the edge of the city above containing prisoners condemned to the much-feared punishment of "dangling." The prisoners are locked in a cage attached to a long chain, which is then flung off the edge of the city-machine and left to dangle, swaying with the city's movement, until the prisoner starves and the cage is hauled back up.Hundreds of dangled prisoners hang from the city at any one time, and the Gutscum sometimes use them as target practice or, on very rare occasions, "rescue" them to induct them into Underbelly gangs, enslave them or pit them against one another in bloody gladiatorial fights. Ambulon folklore maintains that some dangled prisoners have survived for solar months hanging below the city, thanks to divine intervention from the Emperor, and were released when the cage was brought back up again to live saintly lives. In practical terms, however, dangling is a cruel, drawn-out death sentence.