You conjure a homey yet beautiful three-story tower. The tower is made of stone, but it can appear as any other building material of the casters choice. (Wood, metal, etc.)

Each level of the tower is 10 feet tall and the floorplan could either be square or circular in shape with a 20 foot side or diameter, respectively. Access between levels consists of a spiral staircase.

Each level takes one of the following forms, chosen by you when you cast the spell:

Arcane Lab: A lab with a desk, a chair, books, bookshelves, parchments, ink, ink quills, a chalk board and chalk, test tubes and beakers with mysterious liquids in it, and a magical fireplace.

Spa: A washroom with toilets, a large sunken bathtub, a magical brazier, towels, and sauna benches. 

Observatory: An observatory with a large telescope, a balcony, and maps of the night sky

Indoor Garden: Grass floors, benches, butterflies, sunny atmosphere, a beautiful garden, and one way glass walls. 

Conservatory: A room with a stage, one instrument of your choice on stage, and seating for up to 10 people.

Parlor Room: A room with couches, armchairs, a coffee table, bookshelves full of books,  windows, and a piano. 

Kitchen: A room with pots and pans, a stone oven, a sink, cabinets, stain glass windows, and all materials one would need to cook a meal.

Sleeping Quarters: A room with up to 10 beds or less, night stands, windows, and books to read. Each bed space has curtains between them for privacy. 

Training Room: A room with smooth hard wood floors, training dummies, a pull-up bar, wooden training weapons, heavy rocks to lift, and towels.

The interior of the tower is warm and dry, regardless of conditions outside. Any equipment or furnishings conjured with the tower change into fireflies if removed from it. At the end of the spells duration, all creatures and objects within the tower that were not created by the spell appear safely outside on the ground, and all traces of the tower and its furnishings disappear.

Creatures and objects you designate when you cast this spell can move freely into and throughout the tower. All other creatures and objects are barred from passing into it. Spells and other magical effects can't extend into or out of the tower or be cast through it.
As long as the spell is active, the tower is invulnerable. Much like the spell Tiny Hut.

You can cast this spell again while it is active to maintain the towers existence for another 24 hours.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the tower can have one additional level for each slot level beyond 4th.