Create a vibrant vector art design for a t-shirt that captures the essence of urban life in London. The illustration should feature a dynamic cityscape, incorporating iconic landmarks like the Shard, Big Ben, and the London Eye, all rendered in a geometric style. Use bright and vibrant colors, such as shades of blue, red, yellow, and green, to evoke a sense of joy and energy. Ensure the design is suitable for high-quality printing with a clear and transparent background. The composition should be balanced, with geometric shapes adding depth and interest, while a joyful quote in a modern font can be integrated seamlessly into the design, either above or below the cityscape or creatively intertwined with the geometric elements.