The <feImage> SVG filter primitive fetches image data from an external source and provides the pixel data as output (meaning if the external source is an SVG image, it is rasterized.)

The let declaration declares re-assignable, block-scoped local variables, optionally initializing each to a value.

The <line> SVG element is an SVG basic shape used to create a line connecting two points.

Whereas HTML defines a webpage's structure and content and CSS sets the formatting and appearance, JavaScript adds interactivity to a webpage and creates rich web applications.

The instanceof operator tests to see if the prototype property of a constructor appears anywhere in the prototype chain of an object. The return value is a boolean value. Its behavior can be customized with Symbol.hasInstance.

The decodeURI() function decodes a Uniform Resource Identifier (URI) previously created by encodeURI() or a similar routine.

The switch statement evaluates an expression, matching the expression's value against a series of case clauses, and executes statements after the first case clause with a matching value, until a break statement is encountered. The default clause of a switch statement will be jumped to if no case matches the expression's value.

The JavaScript strict mode-only exception "0-prefixed octal literals are deprecated; use the "0o" prefix instead" occurs when deprecated octal literals (0 followed by digits) are used.

The <script> SVG element allows to add scripts to an SVG document.

The <ellipse> SVG element is an SVG basic shape, used to create ellipses based on a center coordinate, and both their x and y radius.