public void sendHighlight(String position, int r, int g, int b){
	JSONObject o = new JSONObject();
	try {
	    o.put("message", "highlight");
	    o.put("coordinate", position);
	    o.put("color", new JSONArray().put(r).put(g).put(b));
	    sendMessage(o);
	}
	catch(JSONException e){}
	catch(IOException e){}
    }