function B_Spline123 (xy,n)
h=100;
for k=1:n-3
w=1;
x=zeros(1,101);y=zeros(1,101);
for t=0:1.0/h:1
for i=0:3
x(w)=x(w)+xy(1,k+i)*B_Base(3,i,t);
y(w)=y(w)+xy(2,k+i)*B_Base(3,i,t);
end
w=w+1;
end
plot(x,y,'-g')
hold on
end