Elf house on a tree! That would be cute in the garden, especially in the tree over grown with ivy. How about some battery tea lights in the windows during outdoor parties. I hear the fairies/elves whispering "home school project" in my ear.
The many small and awkward gap sites left around Oslo has the potential to house several thousand new citizens of the growing city. KIMA and Infill have tried to combine a new business opportunity with high architectural quality.