Writing 和風細雨 (he2feng1xi4yu3; gentle breeze and light rain) with a cat's tail on a water-writing mat.

Water-writing mats turn black when wet and return to their original colour once dry, so they are often used to practise calligraphy with water. The black colour allows you to see your writing clearly, and the mat can be reused as soon as the writing dries and disappears.