Total Internal Reflection (TIR) is a phenomenon that occurs when light rays travel from a denser medium to a rarer medium, provided the angle of incidence is greater than the critical angle for the interface between the two media. This principle is exploited in various applications due to its efficacy in guiding light without significant loss. TIR is a fascinating optical principle with practical applications, including in the design of optical fibers and the brilliance of diamonds. The design of these fibers ensures that light entering one end undergoes multiple total internal reflections along the length of the fiber until it exits at the other end. At the flaws or cracks within the glass, conditions favor light reflecting internally rather than passing through, causing these areas to prominently stand out as brighter.