The Geometry of Compasses; or, Problems Resolved by the mere Description of Circles, and "the Use of Coloured Diagrams and Symbols". By Oliver Byrne. (London: Crosby Lockwood and Co., 1877.) ...

case 1In 2D coordinate system the sum of the angles of all quadrants=360 degree= 2pi radianin (x,y) planeCase 2In 3D coordinate system (x,y,z) I took 3 possible planesi.e.(x,y) (y,z) (x,z)each ...

Venn diagrams typically consist of overlapping circles, with each representing some set of elements, (e.g., things that are cuddly or Broadway shows).