Documents have been stolen from Hillary Black's safe! Or have they?Hillary has opened her safe this morning to find that her crucial documents have been moved around. At first she was sure there were some missing, but now she's not certain.
Always a stickler for patterns, Hillary kept her oddly-shaped documents arranged in the shape of a triangle. And indeed, they're still in the shape of a triangle.
The current shape of the documents is triangle A in the attached image.
Yesterday, Hillary had the documents arranged as triangle B.
The purple square document appears to have vanished, but the triangles look the same.
Has anything actually been removed? And if so, what's the explanation for the similarity of the triangles?
