The 85-year-old, who underwent surgery in December, arrived with her eight colleagues promptly at 10 a.m., walking unassisted to her seat to hear oral arguments.

She smiled slightly and looked about the crowded courtroom, wearing her traditional black robe and lace collar.

The justice went on to ask a total of five questions to counsel on both sides of a patent law dispute, including the very first question. The questions were technical in nature. Her voice was strong, laced with her familiar Brooklyn accent.