A Life's Work in Geometry: An Homage to Hanfried Lenz -- Impossibility of a Certain Cyclotomic Equation with Applications to Difference Sets -- On the Binary Codes of Steiner Triple Systems -- Orthogonal Partitions in Designed Experiments -- Regulus-free Spreads of Content(3, PG) -- Designs, Codes and Crypts-A Puzzle Altogether -- 5-Cycle Systems with Holes -- Stories about Groups and Sequences -- Groups Admitting a Kantor Family and a Factorized Normal Subgroup -- Spreads in Strongly Regular Graphs -- Codes Based on Complete Graphs -- A Construction of Partial Difference Sets in $$ {\mathbb{Z}_{{{p^2}}}} \times {\mathbb{Z}_{{{p^2}}}} \times ... \times {\mathbb{Z}_{{{p^2}}}} $$ -- On the Characterisation of AG(n, q) by its Parameters as a Nearly Triply Regular Design -- The Fundamental Theorem of q-Clan Geometry -- Extension of Gravity Centers Configuration to Steiner Triple Systems -- Constructions of Partial Difference Sets and Relative Difference Sets Using Galois Rings -- m-Systems and Partial m-Systems of Polar Spaces -- Piotrowski's Infinite Series of Steiner Quadruple Systems Revisited.