Consider the market for pens. Suppose that new research has been published stating that the process of writing, erasing, and rewriting improves memorization, leading parents to avoid giving their children pens in favor of pencils. Further, the price of plastic, a major input in the pen production process, has dropped sharply.

On the following graph, labeled Scenario $1,$ indicate the effect these two events have on the demand for and supply of pens.

Note: Select and drag one or both of the curves to the desired position. Curves will snap into position, so if you try to move a curve and it snaps back to its original position, just drag it a little farther.