Tenish ellipses with differently colored top arcs and bottom arcs. in a gnuplot titled 'all-halves'. The ellipses have random eccentricity and orientation, but are heavily overlapping in the picture.
https://gamerplus.org/system/media_attachments/files/114/584/135/688/211/445/original/c1f3a2c6f9b01fe5.png