clear all;clf

a=1;

t=(1:720)./180*pi;

x=a*(t-sin(t));

y=a*(1-cos(t));

plot(x,y,"k-");hold on

t1=t+pi;

x1=a*(t1-sin(t1))-pi;

y1=a*(-1-cos(t1));

plot(x1,y1,"g:")

for i=1:length(t)

h0=plot(x(i),y(i),"ko");

h1=plot(x1(i),y1(i),"ro");

h2=plot([x(i) x1(i)],[y(i) y1(i)],"b-");

pause(0.01);

delete(h0);

delete(h1);

delete(h2);

if i>1

plot(x1(i-1:i),y1(i-1:i),"r-")

end

end