The two circles are reconnected by parabolas. The direct connection by means of the straight line of linear thought is not as effective as the curved parabolas.
parable (n.) “allegorical or metaphorical narrative, usually having a moral for instruction,” late 13c., parabol, modern form from early 14c., “saying or story in which something is expressed in terms of something else,” from Old French parable “parable, parabolic style in writing” (13c.), from Latin parabola “comparison,” from Greek parabolē “a comparison, parable,” literally “a throwing beside,” hence “a juxtaposition,” from para- “alongside” + bolē “a throwing, casting, beam, ray,” related to ballein “to throw” (from PIE root *gwele- “to throw, reach”).