I’m guessing this is the one you’re thinking of:
Yes, there were several made but I think that one got the most exposure. The size of the mirrors, resolution, and limited viewing angles didn’t make for a great gaming experience. I’m sure someone must have tried a larger scale hi-res version.
There are plenty of ‘mirror box’ illusions and also a therapy for amputees that provides visual feedback of a missing limb to help relieve phantom-limb symptoms.
Since we’re here, how does a broken mirror work? If I look in my bathroom mirror, I see my handsome mug smiling back at me. However, if the glass is broken, I’ll see two of me. Both of the “new” mirrors are in the same plane as the original unbroken mirror. Why does the crack in the glass matter?
That’ll only happen if the pieces are tilted relative to each other. Which is likely to be true if something broke the mirror by bashing into it. But if the pieces remain perfectly planar, you’ll just see one of you (with a small gap where the crack is).
It takes only a tiny tilt to give you multiple images. Mirrors are very flat by default.
It only works when you look at it from a particular angle. A small one on a table that you’re looking down at works well. A huge one on an elevated stage that people below are looking at wouldn’t work. They wouldn’t even see the “floating” object. It would ruin the illusion.
It’s a neat trick that you could probably use very well in close-up magic, but I don’t think it would ever work for traditional stage magic.
Many college physics departments have a large parabolic mirror, which can produce a similar effect. One of my professors liked to start class by swinging a baseball bat through a lightbulb that wasn’t there.
Disney’s Haunted Mansion uses similar tricks, as well.
The Exploratorium has a nice one that they keep clean enough that it’s hard to distinguish from reality… except that it’s positioned such that everything is flipped upside-down. Aside from that, it looks totally convincing, with depth cues and everything else looking normal.
There’s one on Amazon for 7.99
I was tempted to buy one of those things for my 9-year-old daughter, I still might. She loves stuff like that. I remember when I bought her a prism so she could make her own rainbows, you’d think I bought her a functioning magic wand.
If you have a flat wall and throw a ball at it really hard, the ball will bounce back at you. Aim a little to the side and it’s going to bounce, come back, miss you, and keep going off into the distance behind you.
But, curve that wall or put a corner in it and you might have a second or third location where you could chuck the ball and have it bounce back to you. For example, you stand in a corner with two walls that are at a right angle to one another and there will be a spot on either wall where you can aim and catch the ball on the bounce-back. Likewise, if you’re in the bottom of a cylindrical well, you can basically throw the ball in any direction you want and it’s going to come back to you (if you’re standing in the dead center).
How ever many places there are in a wall that you could throw a ball real hard and have it come back to you, that’s how many copies of yourself you would see if you painted the wall with mirrors. “bounce” and “reflect” are just synonyms (for this discussion).
Now, as the others say, when you break a mirror, you’re basically creating a very small corner with two flat pieces that are at small angles to one another. If those angles are just right, they might both angle back at you perfectly that they reflect back to the same center point. If you break a wall into bits and angle the parts so they all aim back at you, you can bounce a ball back to yourself in as many ways as you want to. You haven’t done any magic, you’ve just aimed things appropriately so that the bounces go in that direction.
The Haunted Mansion, as I understand it, uses a technique called Pepper’s ghost. It’s a very old trick that’s been widely used in theatre, amusement parks, and magic shows. It actually uses not a mirror, but a sheet of glass, which makes the “ghost” appear translucent. The glass is reflecting something that’s in another room which is hidden from the audience.
Pepper’s Ghost appears to be what was used in a circa 1900 illusion called The Fatal Marriage. I know about it because it was used the first year at Wonderland Park, which I wrote a book about.
The beauty of the illusion is that it works from all angles, at least all angles where you can look into the glass serving as a mirror. And since it works for all angles, it means that objects have the correct parallax and appear properly three-dimensional.
The illusion using the parabolic mirror also works for all lines of sight that let you look into the mirror. And, again, it gives you a true three-dimensional image. As such, it could work for stage magic, but only for a restricted range of angles.
The “Mirage” illusion is a third case of one that givers perfect three dimensional images.
This one is different from the single parabolic mirror, in that it requires two parabolic mirrors, each placed so that its vertex coincides with the focal point of the other. Of course, you have to cut a hole in the upper one. This illusion has such a restricted range of viewing that you treally can’t use it on stage. It’s a “close-up” magic thing.
A fourth trick gives you a reduced image of the object. It was popular in the early 20th century, and is called Tanagra Theater. I wrote an article about it. Although people tried to use this one on stage (It was used in one production of Karel Czapek’s R.U.R.), it really has such an angularly restricted range of vision that it can only be seen b y a small group of observers, close in. It was used in a Ford promotion at World’s Fairs in the 1930s. There’s still one with a “mermaid in an aquarium” at Bimbo’s Bar in San Francisco
(I know they’re still running the mermaid, because I queried them not that long ago, and they replied that it was still up and running)
Various bars used this illusion up until about 1960, but Bimbo’s appears to be the only one still working. The illusion isn’t really perfect, because the image is “squashed” front to back by the same magnification factor, but most people don’t notice this. There are other “shrunken mermaid” illusions, but they generally don’t use mirrors.