Brainteaser #02- Name That Shape -
What three-dimensional shapes have exactly two surfaces?
PS: The answer is not a piece of paper (a piece of paper actually has 6 surfaces as the edges are
technically surfaces).
ANSWER:
A solid cone, a solid hemisphere, a Möbius strip, a hollow sphere (not drawn), and
a half torus (bagel/doughnut shape) cut across/horizontally (not drawn).
PS: It may look as though there are two sides and two edges on the Möbius strip (for a total of
four surfaces), but it's actually ONE continuous side and ONE continuous edge for a total of two
surfaces.
Thank you Andrew Horsfall for letting us know about the second shape.
Thank you Gigi Kerns for letting us know about the third shape.
Thank you Tamilmani for letting us know about the fourth shape.
Thank you Paul McClintock for letting us know about the fifth shape.
And thank you to Amira Winter for the observation that many one-sided three-dimensional shapes become
two-sided when you cut them in half (the example of a starfish was given).
Do you have a
suggestion for this puzzle (e.g. something that should
be mentioned/clarified in the question or solution, bug, typo, etc.)?
