Tenn. Code Ann. § 20-9-303

In the trial of any civil suit, counsel for either party shall be permitted to use a blackboard, models or similar devices, also any picture, plat or exhibit introduced in evidence, in connection with the counsel's argument to the jury for the purpose of illustrating the counsel's contentions with respect to the issues that are to be decided by the jury; provided, that counsel shall not, in writing, present any argument that could not properly be made orally.