To capture the notion of rates of change that can themselves change, we need the concept of a derivative.
First described rigorously by Newton and Leibniz, differential calculus is the mathematics of changing quantities.
A differential equation is an expression that relates quantities and their rates of change. The solution to a differential equation is not simply a number; it is a function.
A non-constant slope describes a rate of change that itself can change.
An oscillator is a function that varies between two values.
The slope-intercept form of a linear equation is a common way to represent the mathematics of change. An example of this concern with relationships is the familiar slope-intercept form of the equation of a line: y = mx +b.

Spontaneous synchronization is a special case of complicated dynamic phenomena. Understanding the mathematics of how, and under what circumstances, entities can come into synchronization with one another provides a starting point for exploring the vast world of nonlinear dynamics.
The Kuramoto Model describes large systems of coupled oscillators.