McHarp represents the collaborative efforts of Texas mother-daughter team of Ruth McNay and Linda Harp. Ruth has been in the pottery business for about 30 years and is known for her interesting wall sculpture. Her daughter, Linda, has a Master's Degree in Anthropology and "the artistic gift of generations." She travels yearly to the British Isles, where she researches the ancient stone carvings, bringing back the lore of each cross and pictures, from which her mother first hand carves the design in clay and then creates a mold. The "McHarp" team creates between 6 and 12 new cross designs each year.

Some common designs in Celtic artwork are knotwork, spirals and key patterns. The knotwork designs were developed by the Celts to a higher degree than anywhere else in the world. Zoomorphic was a knotwork taken to a higher level with designs of animals, beasts and birds with their limbs and bodies twisted into knots.

The spiral is an ancient symbol in which the Celts found their artistic growth. They would often cluster spirals in sacred numbers of three or four.

The Celtic key patterns are also known as mazes. The Celts took this common pattern and set it on a diagonal. They used it in their graphic and sculptural work.