function d =  generate(a)


x1=zeros(a.m,1);
y1=zeros(a.m,1);

x2=zeros(a.m,1);
y2=zeros(a.m,1);

maxim=2*pi*a.n;
step=maxim;
t=step:step:a.m*step;

x1= t.*cos(t) ;
y1= t.*sin(t);
x2= (1+t).*cos(t) ;
y2= (1+t).*sin(t) ;

label=ones(a.m,1);
k=1;
for i=length(x1)+1:1:2*a.m
    j=1+floor(length(x1)*rand);
    x1=[x1,x1(j)+step*rand];
    y1=[y1,y1(j)+step*rand];
    x2=[x2,x2(j)+step*rand];
    y2=[y2,y2(j)+step*rand];
    if(j>a.m)
    label(k)=
    k=k+1;
end

%plot(x1,y1,'+'); hold;
%plot(x2,y2,'r+');

%d=data(['spiral_data' ' n=' num2str(a.n)],x,y); 
%d=data([get_name(d) ' -> ' get_name(a) ' '] ,Yest,Yt);
d=data([get_name(a) ' '] ,[x1' y1';x2' y2'],[ ones(a.m,1);-1*ones(a.m,1);]);
 