Moving Parts was donation perk. It's described as being similar to CraftBook's Toggle Areas, in that it allows save block configuations and toggle between them. The perk mentions that it can be used for "Wings, forcefields, bridges, folding stuffs, and more!". This can perk can be used on both spaceships and towns, making it part of Advanced Shipbuilding and Advanced Machinery.
Only people who have purchased the perk for themselves can toggle Moving Parts, which makes it less than ideal for shared projects.
One can no longer buy this perk; it has been removed from the Store.