When engaging with a new skill or concept for the first time, it’s important to break it down into so that you can take a tractable first step. Unfortunately, that factoring process is itself quite taxing, which may interfere with the object-level material. If the concepts are sufficiently foreign, you may not be able to break it down at all.
Fine-grained task progressions, provided by an expert, can help create Cognitive scaffolding. For example, if you wanted to learn to program, an expert might suggest you first copy a Processing program which says “Hello, Bob!,” then that you might alter the program to print your name instead of “Bob.” Then they might present three different next programs for you to copy and remix: e.g. animating the text across the screen, printing a message multiple times, using color. And so on…
Game designers are particularly good at this (Cook, 2007). The Witness is a great example: each puzzle unfurls one tiny new element of an unfamiliar skill. Later puzzles introduce combinations of those skills incrementally, until finally you’ll find yourself intricately weaving a dozen different new mechanics in creative ways.
Constraints are one way to construct these progressions (Constraints as cognitive scaffolding).
Cook, D. (2007, July 19). The Chemistry of Game Design. Gamasutra. Retrieved from https://www.gamasutra.com/view/feature/129948/thechemistryofgamedesign.php
Thekla, Inc. (2016). The Witness. Berkeley, CA.