Wiktor Gieruszczak contributed to the marcin-filipiak/test_wspolpracy repository by establishing foundational documentation and designing early-stage features over a two-month period. He created and maintained project documentation in Markdown, including a comprehensive README and detailed planning artifacts, to clarify project scope and streamline onboarding. Leveraging C# and XAML, he delivered a prototype for a Sailboat Simulation, accompanied by a functional specification that outlined modules and user interactions. His work focused on technical writing, software design, and UI asset creation, providing a clear baseline for future development. The contributions emphasized clarity, traceability, and readiness for iterative engineering and stakeholder review.