tic();

Setangle(70,-65);
Setwindow([-1.5,1.5], [-1.5,1.5]);

fd=list('z=x^2-y^2', 'x=[-1,1]', 'y=[-1,1]', 'ewsn');
surface=Sf3data(fd, 50, 50);

Windisp(Projpara(surface));

outline=Sfbdparadata(fd, 100);
houtline=BorderHiddenData();
wire=Wireparadata(outline, fd, 10, 10);

Windisp(Projpara(outline));
Windisp(Projpara(wire));


Openfile('tex/surface_sample1_1.tex');
Beginpicture('1.5cm');
Drwline(Projpara(outline), 1.5);
Drwline(Projpara(wire), 0.5);
Endpicture(0);
Closefile();

Openfile('tex/surface_sample1_2.tex');
Beginpicture('1.5cm');
Drwline(Projpara(outline), 1.5);
Setpen(0.5);
Dashline(Projpara(houtline), 1, 0.5);
Endpicture(0);
Closefile();

T=toc();
minute=floor(T/60);
second=floor(T-60*minute);
disp(strcat([string(minute), ' minutes ', string(second), ' seconds']));
