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Draw a picture of a simple polygon and a set of guards, such that the guards can see every point on every edge of the polygon, but the guards cannot see every point in the interior of the polygon.

I encountered this while randomly searching for polygon triangulation problems. I feel that no such polygon + guard combination exists. but I do not know how to go about proving or disproving that. Some help would be appreciated.

Source: Page 17, Problem 1(a) on this document

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A slight explanation of how to form such a polygon would be enough. I cannot find a way to do so. This isn't homework. – vh4x0r Apr 24 '12 at 14:53
    
Ok, I have added some context now. – vh4x0r Apr 24 '12 at 14:55
    
Have you seen this book? – J. M. Apr 24 '12 at 15:02
    
I have an example of this, but I do not know how to include images in an answer. If anybody tells me how, I will draw it (can I do this directly in LaTeX?). – Daan Michiels Apr 24 '12 at 15:20
    
Excellent, thank you! I have found the solution. Should I update the answer myself ? – vh4x0r Apr 24 '12 at 15:20
up vote 2 down vote accepted

This should do it. Yellow stars are the guards. They cannot see the red object.

enter image description here

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