It is easy to create two identical triangles with 6 matchsticks – 3 matchsticks per triangle.
They say it is possible to create 4 triangles with 6 matchsticks. Overlapping is allowed.
What those triangles will be?
The classic solution for this puzzle is creating a tetrahedron (triangular pyramid) as is shown in the diagram’s upper left corner. The tetrahedron’s 4 faces are simultaneously 4 equilateral triangles.
The alternative solution is formed flat on a plane when 2 equilateral triangles are bigger and 2 are smaller as is shown in the diagram’s lower right corner.