visitorIterationNumber = tracker;
if ( g instanceof IGridConnectionVisitor )
{
LinkedList<IGridConnection> nextConn = new LinkedList<IGridConnection>();
IGridConnectionVisitor gcv = (IGridConnectionVisitor) g;
while (!nextRun.isEmpty())
{
while (!nextConn.isEmpty())
gcv.visitConnection( nextConn.poll() );
LinkedList<GridNode> thisRun = nextRun;
nextRun = new LinkedList<GridNode>();
for (GridNode n : thisRun)