Brennan's drawing practice often explores the performative and ritual nature of drawing. There is an emphasis placed on the mediative and contemplative process as a political act whereby Brennan's observations leave minimal disruption of the environment. Short meditative walks source small stones which after been drawn are returned to their source. These drawing ceremonies at times result in miniature handmade books which offer a plank in an argument contra to the current bias toward the gigantic as found in much public art.