A good puzzle is that which the gentleman in the illustration is showing to his friends. 
He has simply cut out of paper an equilateral triangle—that is, a triangle with all its three sides of the same length. 
He proposes that it shall be cut into five pieces in such a way that they will fit together and form either two or three smaller equilateral triangles, using all the material in each case. 

Can you discover how the cuts should be made?

Remember that when you have made your five pieces, you must be able, as desired, to put them together to form either the single original triangle or to form two triangles or to form three triangles—all equilateral.

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Math Genius