N:=3;M:=12;
MON:C-REF(C,N);
MID:=MA(MON,20);
AA:=POW((MON-MID),2);
BB:=MA(AA,20);
CC:=SQRT(BB);
SG:MID+2*CC;
LG:MID-2*CC;
XG:crOSS(MON,LG)COLORBLUE;
N:=3;M:=12;
MON:C-REF(C,N);
MID:=MA(MON,20);
AA:=POW((MON-MID),2);
BB:=MA(AA,20);
CC:=SQRT(BB);
SG:MID+2*CC;
LG:MID-2*CC;
XG:crOSS(MON,LG)COLORBLUE;