A trefoil is a common motif found in gothic architect. In it’s most basic form it consists of three circular elements in the shape of a triangle. This how to describes the construction of a trefoil inside a circle, and is useful when setting out tracery with defined constraints.
Method Of Construction
- Draw a centre line and circle
- Mark the points for the equilateral triangle
- Draw an equilateral triangle
- Find the centre points for lower lobes
- Draw the circles of the trefoil
Draw A Centre Line And Circle
Draw a vertical centre line a-b, and on that line draw a circle with a radius c that you wish to fit the trefoil inside.
Mark Points For Equilateral Triangle
Without adjusting the compass, place it’s point at d where the previously drawn circle intersects line a-b. Draw two arcs e and f at the intersection points with the original circle.
Draw An Equilateral Triangle
Draw an equilateral triangle from points e, f, and point g. Point g is at the intersection of vertical line a-b and the original circle.
Find The Centre Points For The Lower Lobes
Using point e and the centre point of the original circle, construct line e-i. Using point f and the centre point of the original circle, construct line f-h. Points h and and i are the centre points of the lower lobes.
Draw The Circles Of The Trefoil
Place the point of the compass at point h and adjust the radius so that it touches the centre point of the original circle. Draw three circles at points h, i, and j with this radius. The resultant three circles describe a trefoil drawn in a circle with a given radius.
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