A diagram illustrating the minimum unit of learning in a single loop of input, interaction and output. The minimal gain in comprehension is shown as a step upward (yellow) on the axis i. As the lesson moves from a phase of comprehensible input (red) to interaction about the content knowledge (purple), output in approximated form (blue) demonstrates the gain of some i. If you zoomed out from this extreme close-up of learning processes, the yellow step would begin to look like a ramp of increasing instructional challenge. Feedback loops are not visualisable as loops in this edge-on representation.