% defines a profile
x = [1.0 1.8 4.0 4.8 6.8 7.6 8.8 9.4];
y = [1.5 2.0 2.1 2.5 2.5 2.2 2.0 1.5];
plot(x,y)
axis([0 10 0 4])
% to make the profile smoother, we use a spline
xx = 1:0.2:9.4;
yy = spline(x,y,xx);
hold on
plot(x,y,'o',xx,yy);
% to add a wheel
t = 0:0.01:2*pi;
plot(2.5+0.5*cos(t),1.5+0.25*sin(t));
plot(8.0+0.5*cos(t),1.5+0.25*sin(t));