(*This example shows that we can create any 3  D shape from the atomic orbitals  -  
        this is 
what they are for .  Here,  
      we add to the Slater 2  
        s  orbital
 (no node,  
          of the shape of the soccer ball) a small contribution of the orbital,  
3  
        d (x2 - y2) .  
          This implies that we get something similar to the flattened rugby ball .  If we added
3  
        d (3  z2 - z2),  
      the ball would not be flattened*)  
r = (Sqrt[(x^2) + (y^2)])
N1s = (1/(Sqrt[8 π]))
ss = 
      N1s (E^(-(1/2) (Sqrt[(x^2) + (y^2)])))
ContourPlot[ss, {x, -18, 18}, {y, -18, 18}, 
      PlotPoints -> 60]
N3d = (1/((Sqrt[2]) 81 (Sqrt[3 π]) ))
dd = (Sqrt[3]) N3d (E^(-(1/3) (Sqrt[(x^2) + (y^2)]))) ((x^2) - (y^2))
ContourPlot[dd, {x, -18, 18}, {y, -18, 18}, 
      PlotPoints -> 60]
rugby = ss + 0.05 dd
ContourPlot[rugby, {x, -18, 18}, {y, -18, 18}, 
      PlotPoints -> 60]