The TUR (Barato & Seifert 2015) states that for any steady-state current J in a Markov network, the relative fluctuation satisfies: Var(J)/⟨J⟩² ≥ 2/(entropy production rate Σ). This fundamental bound links current precision to dissipation — reducing fluctuations costs free energy. Here we simulate a driven 3-state system and verify the TUR.