The flow layout is represented by the NFlowLayout class. The flow layout is a directed cells layout, which places the cells in lanes, which flow in the current layout direction. The layout direction is controlled by the Direction property. 

Depending on the layout direction the layout uses the HorizontalSpacing and VerticalSpacing to determine the minimal spacing between the vertices and the spacing between the lanes. For a left-to-right direction the horizontal spacing is the minimal horizontal spacing between the vertices, while lanes are spaced with the specified vertical spacing.

The flow layout can be constrained by the size of the layout area in the current layout direction or by an ordinal. The constrain mode is specified by the ConstrainMode property, which takes a value from the CellConstrainMode enumeration: 

• Size - the layout switches to a new lane when the cell, which must be currently placed, will go outside the layout area.
  
• Ordinal - the layout switches to a new lane when the ordinal (number) of the cell in the current lane will exceed the MaxOrdinal property setting.

You can optionally justify the cells in the lanes by setting the JustifyLanes property to true.