This can be useful in plotting the wavefunctions on a bunch of sites. For example say the 1 and 2 column has the x and y coordinates of the sites. The 3 rd column contains the wavefunction amplitude.
pl ‘./fort.80’ u 1:2:($3)*10:3 w p pt 7 ps variable palette
The above command will make both the size of the point and the color bar a function of the wavefunction amplitude.