PROFESSOR PIOTR RONIEWICZ: TEACHER AND FRIEND Pawel Henryk Karnkowski Faculty of Geology, University of Warsaw, Warsaw, Poland When it comes to writing a tribute, we recall images from the past to weave a cohesive narrative - from the last meeting to the first one: how did it all start? The sedimentology aspect of the research was skilfully supported by Piotr Roniewicz, a well-known researcher of fossilised ripple marks, who was astonished by the abundance and diversity of his live observations of ripple marks formed by wave processes. During my third year of studies (1973/74) at the Faculty of Geology of the University of Warsaw, I took an interest in the sedimentology of clastic rocks. [Extracted from the article]