A few years ago I invented a number of peculiar formations made of used tennis balls [1]. Their structure appears to be quite intriguing, especially it regards columnar (3n+1) towers. At the workshop I shall derive the conditions of mechanical equilibria for these “tennis ball towers”. I will also discuss possible applications of these results with issues in physical sciences, in botany, crystallography, nanosciences, etc. [2]. Finally, I am going to show in situ how different tennis ball structures are being built in reality. Everyone attending the workshop will learn on the spot the simple but important practical skills of tennis ball tower making.

• A. Rogava, "Tennis Ball Towers", 32, 25 (2019).
• J. Winkelmann & H.K. Chan, "Columnar structures of spheres: fundamentals and applications", Stanford Publishing (2023).