Nodes of different colours represent the following:
Solid arrows point from a submodule to the (sub)module which it is
descended from. Dashed arrows point from a module or program unit to
modules which it uses.
Where possible, edges connecting nodes are
given different colours to make them easier to distinguish in
large graphs.
determine max number for array (imax) and total number in file
if the first layer is less than 20 cm, adjust to 20 cm if only one layer or second layer is greater than 20 cm