Step 1: Identify the artist of "Of Walls." This celebrated print is a signature work by the Indian artist Anupam Sud.
Step 2: Identify Anupam Sud's primary medium. Anupam Sud is one of India's foremost printmakers, and she is particularly acclaimed for her mastery of the intaglio process, especially zinc plate etching and aquatint.
Step 3: Conclude the medium of the specific work. "Of Walls" is one of her most famous works and is an exemplary piece of etching, showcasing her skill in creating complex, allegorical scenes with deep, rich lines and tones characteristic of the medium.