During 2020, Christmas Corporation developed a patent. Christmas Corp. incurred the following costs related to the development of the patent: tests to perfect the use of the patent for production processes, $7,200 before it was considered viable; research costs in the research laboratory, $25,200; and depreciation on equipment (that has alternative future uses) used in developing the patent, $4,800. In addition, on December 31, 2020, the company incurred legal fees for the patent registration, $8,400. The expected use life of the patent was 20 years, and the expected legal life of the patent was 40 years. On September 30, 2021, Christmas Corporation defended its patent in court after incurring legal fees of $3,600. The total estimated life of the patent at that time was adjusted to 15 years remaining from September 30, 2021 onwards. What is the book value of the patent at December 31, 2021?