For more than fifteen years, ACA members have looked forward to one of the Association’s most unique and engaging traditions: the ACA Puzzle.

Since 2011, Frank Fronczek has generously devoted his time, creativity, and expertise to creating puzzles that challenge, entertain, and inspire our membership. His puzzles have become a beloved feature that blends science, crystallography, and wordplay in a way that only Frank can accomplish.

Creating a great puzzle is no small task. It requires not only deep scientific knowledge, but also creativity, patience, and an appreciation for the curiosity that drives our community. Year after year, Frank has provided puzzles that have sparked friendly competition, encouraged learning, and offered members an enjoyable way to engage with crystallography outside the laboratory and classroom.

On behalf of the American Crystallographic Association, we extend our sincere gratitude to Frank for his remarkable and sustained contributions. Volunteer efforts such as these help make the ACA more than just a scientific society—they help build a community.

Thank you, Frank, for fifteen years of puzzles, challenges, and moments of discovery. Your contributions have enriched the ACA and brought enjoyment to countless members across generations.