Vesica Pisces
 How to construct a Vesica Pisces (two equal circles passing through each other's center),with a given radius and a given common center? 1. Determine the radius and the given common center. 2. Determine the main direction (through the given center). 3. Construct a circle with the given point as its center, and with the given radius. 4. Construct the perpendicular bisector of the righthand half of the centerline (diameter) of circle 3. 5. Construct a circle concentric to circle 3, passing through the intersection of lines 2 and 4. 6. Construct a circle centered at the lefthand intersection of line 2 and circle 5, passing through the intersection of lines 2 and 4. 7. Construct a circle centered at the righthand intersection of line 2 and circle 5, passing through the lefthand intersection of line 2 and circle 5. 8. Circles 6 and 7 together make up the Vesica Pisces to be constructed, are equal, have the given radius, pass through each other's center, and have the given point as their common center.