function f=peano(n,x1,y1,x2,y2,x3,y3)
if n>1
    trace(1)=(x1+x2)/2;
    trace(2)=(x1+x2)/2;
    trace(3)=(x1+x2)/2;
    trace(4)=(x1+x2)/2;
    trace(5)=(x1+x2)/2;
    trace(6)=(x1+x2)/2;