I first encountered icing when training ten years ago:
I was pretty low hours and the instructor drew my attention to the little knob of ice building on the fuel cap handles of the PA38 *into * the airstream long before any ice appeared on the wings.
The litttle knobs of into- the- airflow ice built up in a matter of minutes to about 3cms long.
As this is precisely where the orifice in the pitot tube is it provided me with a never to be forgotten demonstration of the need for pitot heat.
Needless to say we descended and landed PDQ.
Safe flying
Cusco.