t = (1/8:2/8:15/8)'*pi;  % column vector
x = sin(t);
y = cos(t);
fill(x,y,'r')  % a filled red circle using only 8 points
axis('square')
text(-0.11,0, 'STOP')
title('Red Stop Sign')
disp(['Press a key to continue'])
pause;

t = 0:0.05:2*pi;
x = sin(t);
fill(x,t,'b')
disp(['Press a key to continue'])
pause;

colormap(hsv)
fill(x,t,x)
