Architect Shinsuke Fujii accepted the challenge from a client who wanted an accessible tall bookshelf that would not be affected by an earthquake. One entire wall of the house is slanted outward to allow climbing without any chance of tipping over.
Via Spoon & Tamago:
The client, who happened to be an avid book lover, approached Fujii with the task to design a home around a large bookshelf that's both easily accessible but also one that won't spill all the books if there's ever a tremor.
The solution was to slant the entire western-facing façade and create a built-in slanted bookshelf whose shelves also function as a ladder. The slant allowed family members of all ages to climb up and reach books, but also keeps the books from falling should an earthquake ever shake the home. The slanted façade also had the effect of creating an open feeling in the family room, where the home's high perch allowed for plenty of sunlight to enter through the large windows.
The slant continues to the outside of the house:
• Japanese Home Designed Around a Climbable Bookshelf (Spoon & Tamago)