Given two curves C_1 and C_2 and a fixed point O, let a line from O cut C_1 at Q and C_2 at R. Then the locus of a point P such that O P = Q R is the cissoid. The word cissoid means "ivy shaped." curve 1 | curve 2 | pole | cissoid line | parallel line | any point | line line | circle | center of circle | conchoid of Nicomedes circle | circle tangent line | on circumference | oblique cissoid circle | circle tangent line | on circumference opposite tangent | cissoid of Diocles circle | radial line | on circumference | strophoid circle | concentric circle | center of circles | circle circle | same circle | (asqrt(2), 0) | lemniscate