// Import the electron density field
electrondensity = Import("watermolecule");

// Partition for parallelism
electrondensity = Partition(electrondensity);

// Compute the gradient of the electron density field
gradient = Gradient(electrondensity);

// Create a camera
camera = AutoCamera(electrondensity,"off-front");

// Create approximately 10 starting points, scattered through the data 
starts = Sample(electrondensity, 10);

// Compute the divergence and curl of the gradient field. We will use the
// curl to put twist on the streamlines
div, curl = DivCurl(gradient);

// Create streamlines from each of the starting points created by Sample.
// The curl is used to give a twist component to the lines, based on the
// vorticity of the vector field.
lines = Streamline(gradient, starts,curl=curl);

// Map the original electron density onto the lines, and color using 
// AutoColor
streamlinesmapped = Map(lines,electrondensity);
colored = AutoColor(streamlinesmapped);

// Create ribbons of width 0.2 in user units.
ribbons = Ribbon(colored,width=0.2);

// Display the ribbons
Display(ribbons,camera);