Object oriented programming is the first of countless Xerox PARC inventions.
Vastly simplifying, there are two ways to program a computer. In procedural programming, each thing the computer does is listed. Conditional statements tell the computer which path to follow.
Comparatively, in object-oriented programming, objects mimic real life. Programmers then act on these objects.
For example, a tree object might have three sub-objects, an oak, a maple, and cherry tree. All three tree types would have a different look when drawn. Each could be chopped down and they’d all be affected by wind. Similarly, if a car drove into a mature tree the car would suffer. However, if a car drove into an immature sapling, then the tree would suffer. There is no need to reprogram the computer for each type of tree.
Many Xerox PARC inventions were the, um, “inspiration” for Steve Jobs and Apple to build the Macintosh. But Jobs did not take Smalltalk and object-oriented programming, something he later regretted.