int phcset(char *clf,int col = 1)
{
// Macro phcset.C:  This macro operates upon the TGeometry class
// phobos (which must have been loaded) to set visible and of
// color number col all nodes beginning with the two characters
// clf; for example "SN", 6 will show one spectrometer arm sensitive
// silicon in purple.   There are also two special cases, U* and E*.
//    DMcL 1/Sep/97

// Declarations (PhNode, phobos are in scope from calling routines)
  TList *phList;
  TIterator *phIter;
  Text_t *phName;
  Bool_t phFlag;

// Set up to iterate over all the phobos geometry nodes
  phNode = phobos->GetNode("OUTS1");   //Top node, reference frame
  phFlag = 0;

//      Need list at lower "tree" level... top level gives OUTS1 only
  phList = phNode->GetListOfNodes();
  phIter = phList->MakeIterator();

//  get the first node under OUTS1
  phNode = (TNode *) phIter->Next();

//  Cycle through nodes, which all depend on OUTS1
  while (phNode)    // generally, set attributes according to node name
  {
    phName = phNode->GetName();

// Carry out all operations on all individual nodes:

//  This is the usual match of the first two characters
    if (strncmp(phName,clf,2) == 0)
    {    
        phNode->SetVisibility(1);
        phNode->SetLineColor(col);
    }

//  But we have two special cases, U* and E*:
//     U* denotes all starting with U except UP, UN
    if (strncmp(clf,"U*",2) == 0)
    {
        if((strncmp(phName,"U",1) == 0)
        && (strncmp(phName,"UP",2) != 0)
        && (strncmp(phName,"UN",2) != 0))
        {
           phNode->SetVisibility(1);
           phNode->SetLineColor(col);
        }
    }
//     E* is for electronics boxes
    if (strncmp(clf,"E*",2) == 0)
    {
        if(strncmp(phName,"E",1) == 0)
        {
           phNode->SetVisibility(1);
           phNode->SetLineColor(col);
        }
    }

// End of operations on nodes; handle looping with subtrees.
//    Here we had to add some complication, hard-coded to the PMC
// phobos geometry i.e. it is organized in a three level tree
// according to convenience in defining rotations, unrelated to
// the component's (node's) function.
    if(phNode->IsFolder())  //Contains nodes also (only one more level)
    {
        phFlag = 1;   // set condition and initialize subtree loop
        TList *phsList;
        TIterator *phsIter;
        phsList = phNode->GetListOfNodes();
        phsIter = phsList->MakeIterator();
    }
// Alternative if we are in a subtree
    if(phFlag == 1)
    {
        phNode =  (TNode *) phsIter->Next();
        if (!phNode)
        {
           phFlag = 0;
           delete phsIter;
        }
    }
    if (phFlag == 0) {phNode = (TNode *) phIter->Next();}
  }
  delete phIter;
  c1->cd();
}