function z = equilateral(x, y) N = length(x); z = zeros(N,1); x1=x(1); y1=x(2); x2=y(1); y2=y(2); z(1)=(x1 + x2 + sqrt(3)*(y1-y2))/2; z(2)=(y1 + y2 + sqrt(3)*(x2 - x1))/2; end