To arrange nodes in a Sugiyama layout:
All nodes in the active window are arranged according to a Sugiyama layout, a layered, tree-like layout that tries to minimize crossings.
Note: [2.25in] The graph in the active window cannot have cycles.
If the number of nodes in the tree is too great, or
the hierarchy is too deep, or you run out of virtual
memory, the Sugiyama implementation fails.