Mobile Construction Yard, or MCY, are Command and Conquer inspired (and read shameful ripoff) vehicles used by the Eleutheroi factions in the First Lampardian War and the game Cyan Sphere of Doom: Galactic War and Imperium Novum. As stated above, the MCY are an homage to the Mobile Construction Vehicles of Command and Conquer, and even hosts all of its functionalities: innate building and the ability to pack and unpack.
The MCY makes the debut at the Mundane Exploration of Cyan Sphere of Doom, supplied by a Sentinel survivor of a Sentinel settlement ransacked by the infantids, but later on found by Areus Megas who took the Destinybringer. The construction yards are not mobile in the game, but has the functionalities of the yard, building mini-structures to assist Areus in his adventures.
The MCY is used by both the Eleutheroi factions in the game. MCY are tough but unarmed just as their original counterparts were, and are able to build all the structures of the respective factions.
Since the author of this article (yours truly) started to give a f**k about copyrights to deviate away from the CWC-style travesty starting with the dekirbyization of the Spheres via conversion to Lagikoi, MCY does not make an return. However, the spirit of C&C style building remains in the Posterity faction, which has the Command Base and the Pandora.