Brain Teaser

Art gallery problems involve finding an unmoving guard (or guards) who can "see" the entire gallery. A guard is able to see any part of the gallery that can be connected to its position by a straight line without intersecting any walls.

What is the least number of guards needed to completely guard this gallery of bovine art?

The guards cannot move, and every part of the gallery must be in the line of sight of at least one guard.

  • 2
  • 3
  • 4
  • 5

 

3 Guards

Why is 3 guards the absolute minimum?

Strong Hint:

 

 

By the following diagram, we can place two guards at mirrored positions near the wings.  They can then see their wing and the front part.

Another guard at the bottom should be placed, so he can see the bottom part as well as some top part unnoticed by the other two guards.

  • Problem by BRILLIANT
  • Solution by BRILLIANT
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