View difference between Paste ID: n7RF6rxt and BsfyXu02

 import geometry;
 import patterns;
 import markers ;
 //import graph;
 //import three;
 defaultpen(fontsize(11pt));
 dotfactor=5;
 //labelmargin=0.25;
-add ("hatch",hatch (1.2mm , black ));
+
 point A,B,C,E1,L,O,K;
-point A,B,C,A1,B1,C1;
+A=(0,0); C = 5*dir(0); B=3.5*dir(74);
-C=(0,0); A = 3*dir(0);
+line AB=line(A,B); line AC = line(A,C);
-B=2.5*dir(60);
+line BC=line(B,C);
-A1 = C + 1/3*(B-C);
+line l1 = bisector(AB,AC);
-B1 = A + 1/3*(C-A);
+line l2 = bisector(AB,BC);
-C1=  B + 1/3*(A-B);
+
 E1 = intersectionpoint(l1,BC);
 L = intersectionpoint(l2,AC);
-dot(C); dot(A); dot(B);
+O = intersectionpoint(l1,l2);
-dot(A1); dot(B1); dot(C1);
+K = projection(A,L)*B;
 draw(A--C--B--cycle,black+1bp); draw(A--E1);
-draw(C--A--B--cycle);
+draw(B--L); draw(B--K);
-draw(A1--C1--B1--cycle);
+draw(A--L, white+opacity(0), StickIntervalMarker(2, 1, size=0.15cm));
 
-filldraw(A1--C1--B1--cycle,pattern ("hatch"));
+dot(A,black+4bp); dot(A,white+3bp);
 dot(B,black+4bp); dot(B,white+3bp);
 dot(C,black+4bp); dot(C,white+3bp);
-label("$C$",C,SW); label("$A$",A,SE); label("$B$",B,N);
+dot(E1,black+4bp); dot(E1,white+3bp);
-label("$A_1$",A1,W); label("$B_1$",B1,S); label("$C_1$",C1,E);
+dot(L,black+4bp); dot(L,white+3bp);
 dot(O,black+4bp); dot(O,white+3bp);
 dot(K,black+4bp); dot(K,white+3bp);
 
 markangle(1,radius=0.5cm,C,A,E1);
 markangle(1,radius=0.6cm,E1,A,B);
 markangle(2,radius=0.6cm,A,B,L);
 markangle(2,radius=0.4cm,L,B,C);
 markrightangle(size=0.25cm, B,K,A);
 
 label("$A$",A,SW);  label("$C$",C,SE);  label("$B$",B,N);
 label("$E$",E1,NE); label("$L$",L,S); label("$O$",O,1.1W);
 label("$K$",K,NE);
 label("$3a$",A--L,S); label("$b$",L--C,S);
 label("$6a$",A--B,W); label("$4a$",B--O,E); label("$2a$",O--L,E);
 label("$2b$",E1--C,2E);