Vasileios Peilivanidis expanded simulation capabilities in the quantumlib/Cirq repository by adding CSWAP (Fredkin) gate support to the ClassicalStateSimulator, enabling accurate simulation of Fredkin circuits and addressing a gate-specific crash through targeted Python development and testing. He also updated the PennyLaneAI/qml tutorial on qubit rotation, revising documentation to clarify the use of JAX-based optimization and replacing outdated Autograd references. His work demonstrated careful attention to cross-repository consistency, adherence to contribution guidelines, and a focus on reducing onboarding friction for users. Throughout, he applied skills in Python programming, quantum computing, and documentation to deliver robust, maintainable improvements.