connection between CST and MATLAB

clear all 
N = 10; % number of full turns;
step = pi/12; % discretization step (orig pi/6) 
b = 0.3; % separation between turns in mm 
a = b*step*4/(1-cos(step*4)); % offset from center in mm %orig
a = b*step/(1-cos(step)); 
n = 1; % power 
theta = [0:step:2*pi*N]; 
r = a + b*theta.^(1/n); 
x = r.*cos(theta);
y = r.*sin(theta); 
theta = theta + pi;
r1 = a + b*theta.^(1/n);
x1 = r.*cos(theta);
y1 = r.*sin(theta); 
plot(x, y, 'b', 'LineWidth', 2); 
grid on;
hold on; 
plot(x1, y1, 'r', 'LineWidth', 2); 
grid on; hold on; 
axis('equal'); 
title('Units - meters') 
z = [x' y']; 
save('spiral1_new.txt','z','-ASCII');
z = [x1' y1'];
save('spiral2_new.txt','z','-ASCII');