In the early 2000's I took a short trip to Amsterdam and Rotterdam. While exploring the streets of Rotterdam I stumbled upon the rather odd looking houses pictured below. The houses are cubes that are set at about a 55 degree angle and positioned upon hexagonal plinths. On first sight the houses are very striking and confusing to the eye, it certainly takes a bit of thought to try to imagine what they would be like on the inside.
It cannot be easily seen from the picture below, but the houses do in fact look like trees when viewed from the correct angle, and it seems that the design philosphy behind the Cube Houses was to create high density housing while leaving space at ground level.
Perhaps the designer had spent some time in Amsterdam himself, before designing these houses!