Probably not all doors should offer previews, all the time, but this is undeniably wonderful. As it is, the knob offers bi-directional viewing; I wonder if you could half-silver one side and make it one-way? Johnny Strategy at Spoon & Tomago writes:
In conjunction with Design Tide Tokyo, architect Hideyuki Nakayama – a protÃ©gÃ© of Toyo Ito – has teamed up with UNION, a manufacturer of door handles and levers, to create a glass globe doorknob. As you approach the doorknob you catch a glimpse of what appears to be another world, waiting for you to enter and join, but in fact is a reflection of the room on the other side of the door.