% spirale
t=4*pi:pi/300:6*pi;
x1=t.*cos(t);
y1=t.*sin(t);
x2=[4*pi 6*pi];
y2=[0 0];
x=[x1 x2];
y=[y1 y2];
X=['u.*cos(u)'];
Y=['u.*sin(u)'];
XX=['-u.*sin(u)+cos(u)'];
YY=['u.*cos(u)+sin(u)'];
