title: plot a 3d point in MatLab
body: <p>I'm trying to plot just one point in any coordinate system: Cartesian, cylindrical or spherical.</p>
  
  <p>I tried <code>plot3(1,1,1)</code> with many values but just shows a tiny point in the same location for all values! I tried <code>surf(X,Y,Z)</code> as well but matlab said: Z must be a matrix, not a scalar or vector.</p>