public Instance replaceSymbol(Symbol symbol,int depth,Transform matrix2,AlphaTransform cxform,int ratio,int clipDepth){
  Transform matrix=matrix2;
  Instance inst=new Instance(symbol,depth);
  if (matrix == null) {
    matrix=new Transform();
  }
  Placement placement=new Placement(inst,matrix,cxform,null,ratio,clipDepth,frameNumber,false,true,null);
  placements.add(placement);
  return inst;
}

public Instance replaceSymbol ( Symbol symbol , int depth , Transform matrix2 , AlphaTransform cxform , int ratio , int clipDepth ) { Transform matrix = matrix2 ; Instance inst = new Instance ( symbol , depth ) ; if ( matrix == null ) { matrix = new Transform ( ) ; } Placement placement = new Placement ( inst , matrix , cxform , null , ratio , clipDepth , frameNumber , false , true , null ) ; placements . add ( placement ) ; return inst ; }
replace the symbol at the given depth with the new symbol
