Flower type figure in MATLAB (with concept of unit circle plotting in MATLAB)

CODE:

t=0:0.001:2*pi;
x=cos(t);
y=sin(t);
t=x.*y;
plot(x,y,'g','linewidth',8);
hold on;
plot(x,t,'r','linewidth',8);
hold on;
plot(t,x,'b','linewidth',8);
hold on;
axis square
hold on;
t=x.*0.5.*y;
plot(t,x,'c','linewidth',8);
hold on;
plot(x,t,'m','linewidth',8);
hold on;
plot(t,x,'c','linewidth',8);

How to plot unit circle in MATLAB?