pg=cell(2,6);
ns=[3 4 4 4 5 6];
for in=[1 3 5:6]
  n=ns(in);
  p=0:n;
  L=1/sin(pi/n)/2;
  pg{1,in}=L*(1-cos(2*pi/n*p));
  pg{2,in}=L*(sin(2*pi/n*p));
end

p=0:4;
pg{1,2}=cos(pi/5)*(1-cos(2*pi/4*p));
pg{2,2}=sin(pi/5)*sin(2*pi/4*p);
pg{1,4}=sin(pi/5)*(1-cos(2*pi/4*p));
pg{2,4}=cos(pi/5)*sin(2*pi/4*p);
