| OTTO direct view | 
|
The answers are:
| View | "look" |
| (1) | (a) |
| (2) | (e) |
| (3) | (b) |
| (4) | (b) |
| (5) | (e) |
| (6) | (e) |
| (7) | (c) |
| (8) | (c) |
| (9) | (e) |
You can see these situations in the sequence of photographs below. Each photograph contains two views: the view through the side closest to the camera and the view of the internal reflection off the side opposite the camera. Notice that you cannot see any likeness of OTTO through the sides of the plastic block. A very elegant proof of this has been derived by John Roeder in The Physics Teacher, Volume 45 (March 2007), page 182, in an excellent short article called Why Light Won't Refract Through Adjacent Faces of a Cube, PDF or Word format.
You can see a reflection of OTTO off the opposite internal side of the block, as seen in each photograph. Note that these internal reflections are inverted front-to-back, with each inner surface acting as a plane mirror. See Question of the Week #18 (Archive 1) for a more detailed discussion of reflection from a plane mirror. Each of the pictures showing the internal reflection of OTTO also show a bit of the direct downward view for comparison. The direct downward view of OTTO, called "look (a), is reproduced below.
| OTTO direct view |
|
| Front: views (6) and (7). | 
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| Left: views (2) and (3). | 
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| Back: views (8) and (9). | 
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| Right: views (4) and (5). | 
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Question #298 is a follow-up to this question.
