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.Noticed mistape? Highlight it and press Ctrl+Enter, to inform us.
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ELLIPSOGRAPH
ELLIPSOGRAPH — is the name of this simple device. It can be used to draw an ellipse with any ratio of the semiaxes. It is enough to set into the holes on the line of alignment pins to...
END-EXPRESS
For more convenient use of masking tape or duct tape, there are special tapes with a knife, not giving to the same after use to stick the remaining end. In the absence of such a device...