1) Draw a horizontal line. This will be the horizon line that the whole drawing is based on.
2) Open the compasses to about 4 cm. Measure this against a ruler. Place the point of the compasses in the paper at the horizon line. Holding the top of the compasses, draw a circle.
3) Move the compasses to the point where the circle cuts the horizon. Make sure that the arms of the compasses are still open at the same distance. Holding the top of the compasses, swing an arc that is just over a semicircle in size.
4) Move the compasses to the other side, where the circle cuts the horizon and repeat.
5) Now you need to add the vertical line. If you have a set square, use this. Otherwise, move the compasses to the point where the arc of the semicircle cuts the line of the main circle (highlighted in blue). Swing a small arc. Repeat on the other three intersections. Carefully line up the ruler with the points where the two sets of (blue) arcs cross. Draw a line between them.
6) With the compasses still at the same radius as the very first circle, move them to the point where the vertical line cuts the main circle. Draw a semicircle. Repeat at the other point, where the vertical cuts the main circle. This gives four ‘petals’. These shapes are known as Vesicas. NEXT
diagram: Diane George
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