“BOOM” — CENTER

For a couple of minutes of paper or paperboard will be able to make strenuously device that will instantly show you the centre of any circle, for example, the base of the cylinder. The secret lies in the fact that the rays arrows, encircling a circle located at an angle of 90° to each other, and a “shaft” of the arrow divides this angle in half, and it always passes through the center.

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