function sierpinski(x,y,z,n)
%x為初始三角形的第一個頂點的坐標
%y為初始三角形的第二個頂點的坐標
%z為初始三角形的第三個頂點的坐標
%n為迭代次數
x1=x(1);
x2=x(2);
y1=y(1);
y2=y(2);
z1=z(1);
z2=z(2);
for j=1:n
  a1=[];
  a2=[];
  b1=[];
  b2=[];
  c1=[];
  c2=[];
  for i=1:length(x1)
    a1=[a1,x1(i),(x1(i)+y1(i))/2,(x1(i)+z1(i))/2];
    a2=[a2,x2(i),(x2(i)+y2(i))/2,(x2(i)+z2(i))/2];
    b1=[b1,(x1(i)+y1(i))/2,y1(i),(y1(i)+z1(i))/2];
    b2=[b2,(x2(i)+y2(i))/2,y2(i),(y2(i)+z2(i))/2];
    c1=[c1,(x1(i)+z1(i))/2,(y1(i)+z1(i))/2,z1(i)];
    c2=[c2,(x2(i)+z2(i))/2,(y2(i)+z2(i))/2,z2(i)];
  end
  x1=a1;
  x2=a2;
  y1=b1;
  y2=b2;
  z1=c1;
  z2=c2;
end
for i=1:length(x1)
  fill([x1(i),y1(i),z1(i),x1(i)],[x2(i),y2(i),z2(i),x2(i)],'b');
  hold on
end
hold off