I have been building this tower for 3 years. It is 144 square feet, 11×13 footprint. It has two floors and towers a grand 23 feet in height.
Being in the city, my footprint was restricted to 144 sq ft, however, in the city books, I was permitted to go up as high as an 18 foot mid-eave and my total height being 23 feet.

Backyard tiny house in Portland, Maine. Build by Kelly Nesbitt.