'Bing and Flop build a sandcastle, and Pando joins them in the sandpit with his wind-up digger toy to help'. Bing and Flop are building a sandcastle when Pando joins them in the sandpit with his wind-up digger toy to help. Bing finds a lovely 'poiky thing' in the sand and thinks it will make the perfect decoration for the top of his castle - not realising it belongs to Pando's digger.