Hin Ta and Hin Yai, some fascinating rock formations on Koh Samui’s south coast, have been a source of mirth and wonder on the island since they were discovered by the locals many years ago. Art often imitates Nature, but less common is Nature imitating Art, especially the Art of the Ribald. But in Thailand anything is possible and these rocks, known as Grandpa (Ta) and Grandma (Yai), look, respectively, like male and female genitalia.