code: public void addStep(Diagram diagram) {
  		if (diagram.getFigureCount() != figures.size()) {
  			throw new RuntimeException("Mismatched diagrams, missing ids");
  		}
  		for (int i=0;i<diagram.getFigureCount();i++) {
  			Figure figure = diagram.getFigure(i);
  			String id = figure.getData().getMetaData();
  			
  			for (int j=0;j<figures.size();j++) {
  				Figure existing = (Figure) figures.get(j);
  				if (existing.getData().getMetaData().equals(id)) {
  					MorphShape morph = (MorphShape) existing.getShape();
  					morph.addShape(figure.getShape());
  					break;
  				}
  			}
  		}
  	}
docs: Add a subsquent step to the morphing
  
  @param diagram The diagram to add as the next step in the morph