Teach, test, twist
Also said as Kishōtenketsu in levels, Introduce, develop, twist
A way of building a level around one idea: show it somewhere safe, ask for it where failure counts, then change it so that what you learned has to bend. Then move on.
Players learn from doing, without text, and the game never asks for something it has not shown. Each idea also gets used up and left behind before it grows stale.
Say it
“Give the bounce pad three rooms. Room one: a pad in front of a wall, with no way to die. Room two: the same pad before a pit. Room three: two pads in a row, and you press in mid-air.”
Where you’ve seen it
Koichi Hayashida, director of Super Mario 3D Land, has described building levels in four steps, drawing on the four-part story form kishōtenketsu: introduce an idea, develop it, twist it, conclude. He said 3D Land is where he grew strict about it.
Not to be confused with tutorial
A tutorial stops the game to explain itself. Teach, test, twist does the teaching inside the level, so it never looks like teaching.