A nine-scene guided mini-lesson: y = x² − 6x + 5, y = (x − 1)(x − 5) and y = (x − 3)² − 4 are the SAME parabola — each form hands you a different part of the sketch for free, and each is then shown again with a = −2 so you can see what a negative, non-unit a does. Prev / Next drives the story (← → keys work too) — or press ▶ Play all and let it read itself aloud.