21.   Above the desk were two doors, each with a carved shell at its top, that opened onto the bookcase.

22.   Ahead, a small antechamber opens onto the small salon, where pinpoints of light lead the eye magnetically forward.

23.   All carry only two or three skiers a chair, and most open onto knife-edged ridges that cannot accommodate many people.

24.   All the bedrooms except one open onto a swimming pool.

25.   But the framework for the room, which features a wall of mahogany framed windows and doors opening onto the terrace, is there.

26.   But the ways in which the box is rearranged to suggest different perspectives, with doors opening onto the emptiness of the night beyond, are stunning.

27.   Click, and the digital landscape opens onto complex puzzles, new vistas or other lands.

28.   David C. Sher depicts a flying witch with a bulging stomach that opens onto toothy jaws.

29.   Each opens onto a private balcony with a sweeping view of the Grand Tetons to the southwest.

30.   Four large windows opened onto the street, the summer air circulated by a cooling fan.