IPT2018-Problem11- Chalk on the Water (Voronezh State University, Russia)

IPT2018 Problem 11 Chalk on the water Voronezh State University: If you draw a line on a glass surface covered with a thin layer of water using chalk, the line will blur in offshoots distributed in the lengthwise direction. What are the statistical properties of this distribution and how do they depend on the important parameters?