The canonical Creo Terram spell for creating a covenant’s tower is excellent, however it is also expensive in vis in the caster only wishes a smaller dwelling. This is a version which creates a simpler and smaller keep.
Conjuring the Magi’s Home
Creo Terram 20, R: Touch, D: Mom, T: Individual, Ritual
A simplification on the Conjuring the Mystic Tower to create a modest keep with ample space as a home and laboratory. The keep has a battlement on top, three generously proportioned levels above ground, adjoining stairs, and a small cellar in the foundations below.
The spell provides 100 cubic paces of stone, which allows for walls 6 inches to one foot thick, stairwells, multiple rooms for a solar and servants, corridors, and a standard sized Magi’s lab on the upper floor. The complexity modifier allows for the structure to be a single piece of stone with shutters, doors and such built in. When small parts are needed they are created within the single piece using thin stone slivers.
(Base 3 to create stone, +1 Touch, +2 size, +2 complex design, ritual)
These effects, like all the others I’ve pondered are part of a new spells compendium for Ars Magica.