The article explains how to transform numbers from one range to another using simple arithmetic like multiplication, division, addition, and subtraction.
It uses a faux-3D carousel as an example, starting with angles in turns (0 to 1) and mapping them to radians, then to screen coordinates via sine and cosine.
By applying scaling, translation, and trigonometric functions, carousel elements are positioned in a squished circle with depth effects such as z-index, scale, opacity, and blur.
The author demonstrates step-by-step mapping from [0,1] to other ranges, emphasizing the simplicity of starting with a [0,1] range to solve complex problems.
A general formula is provided to map any range [A,B] to [C,D]: v = C + (v0 - A)/(B - A)*(D - C).
The technique is applicable beyond graphics, e.g., easing functions, dollar-to-million conversions, or random number generation.