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Unfolding the impossible: turning a sphere inside out, without a single crease.
This video is about the problem of turning a sphere inside out, by passing the surface through itself, without making any holes or creases. Mathematicians believed the problem to be unsolvable until 1958, when Stephen Smale proved otherwise. The motion of turning a sphere inside out, called a regular homotopy, is extremely difficult to visualize. The homotopy in this film was developed by Bernard Morin, a blind mathematician. The motion is illustrated with a sequence of chicken-wire models, built by Charles Pugh, showing the crucial stages in the motion. Commentary is provided by mathematicians Nelson L. Max, Stephen Smale, and Charles Pugh, and by physicist Judith Bregmann.
No cast information available.
No crew information available.
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Before Macintosh: The Apple Lisa
2024
Twisted Retreat
2026
Sign in to vote
Battle your watched movies head-to-head
Community Top Movies
Evil Dead II
1987 · 14 wins
The Dark Knight
2008 · 14 wins
Halloween
1978 · 13 wins
Final Destination
2000 · 12 wins
Halloween II
1981 · 11 wins
Trivia
Leaderboard →Playing as a guest — sign in to save your score and rank on the leaderboard.
Movie Trivia
Guess the movie from a clue — tagline, plot, cast and more. Pick from four posters.
What movie experience do you prefer?
What is your favorite movie genre?
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