)M0capm0 %]1@ `|4y "h`  |'  p1H   XahLee.org, 2004.   0 @   1fk |'Q0(AePe@eVeVAet,.+IH +CBB $ |'B;;0YP;ް ;D@CK  |'AY;6OTHACK o) ti |'r join must contain a third, say . Suppose ABCD /\\ O==APC'D'. Then AP//'TisPoints A,B,C,D is a harmonic set H(AB,CD). If we let A and B be fixed, the position of D will be determined by the position of C. This suggest mapping X->X' defined as H(AB,XX'). On the other hand, we can have points A and C fixed, then we have a mapping X->X' defined as H(AX,CX'). Drag point C to see the mapping H(AB,XX'), drag point B to see the mappings H(AX,CX').=/PP=Fp6H6„=+6H'6È6eV' |'j; Y`; Y6;;ACKD@CK?PU? |' C@05tAePe@eVeVAet,.+IH sCpCK >| |' B0(AePe@eVeVAet,.+IH +C_CK >Rz |' A@05tAePe@eVeVAet,.+IH sCCK ' |'n Y7P7ހ;77CpCKCBB?Z' |'l H077 0;7 7CBBC_CK?0' |'k Y\7P 77@;7@7CBBCCK? ? |' S@05tAePe@eVeVAet,.+IH sCjÎC@, e<@  |'v<@ [ HH;<@0[|CjÎC@,CBB? ' |'m Y,here exists 77;77CjÎC@,CCK? 7 |'P0(AePe@eVeVAet,.+IH +C~C^  e  |'y Y< `P `6hPPC~C^CBB?   |'u[@;66,`<<<???>6#CaiyBQմC~C^?1k  |'w0[4< ϐ6h6ü66<6CBBCaiyBQմ?L'm |'p Ying a triang7p7p;7p7CjÎC@,CaiyBQմ? 7  |'D0(AePe@eVeVAet,.+IH +CoCK