MetaPost Previewer by Troy Henderson
来源： MetaPost Previewer by Troy Henderson
path pat[];
pair p[];
u=10pt;
h=4u; w=8u;
pat.0=(0,0)–(w,0)–(w,h)–(0,h)–cycle;
pat.1=(w/2,0)–(w/2,h);
z1=(.1w,h); z2=(.4w,h); z3=(.7w,h); z4=(.9w,h);
z5=z1-h*up; z6=z2-h*up; z7=z3-h*up; z8=z4-h*up;
pat.2=z2{dir -90}..z3{dir 90};
pat.3=z5{dir 85} .. tension 2 .. z7{dir -90};
pat.4=z1–z6;
pat.5=z4–z8;
pickup pencircle scaled 3pt;
dotlabels.top(1,2,3,4);
drawdot(z5); drawdot(z6);drawdot(z7);drawdot(z8);
pickup pencircle scaled 1pt;
draw pat.0;
draw pat.1 dashed evenly;
draw pat.2; draw pat.3; draw pat.4; draw pat.5;
