Entropy is the measure of randomness or chaos. Other games use spinners, timers of random length, or other sources of randomness. It is important to disambiguate algorithmic randomness with stochastic randomness. Kolmogorov used this theorem to define several functions of strings, including complexity, randomness, and information. Irregularity and local representativeness affect judgments of randomness. It is for this reason that randomness is ubiquitous in cryptography. This is a classic example of a PUF using intrinsic randomness. Yongge Wang showed that all of these randomness concepts are different. This measure of deviation from randomness was called sigma. These functions are used as a numerical representation of the "randomness" found in nature. Another case is software that relies on randomness for fair distributions of results. Turbulence is flow characterized by recirculation, eddies, and apparent randomness. Wing venation patterns are also divergent to apparent randomness. There are several ways to measure and use clock drift as a source of randomness. The invention of calculus had a positive impact on the formal study of randomness.