Run and then click in the slot of the external field slider to increase the field to H=1. The magnetization grows by an increase in the width of the red domains at the expense of the white. (To update the graph, stop briefly and run again.) Click the field back to zero and, after some time, the magnetization returns nearly to zero.
Now increase the field to 2.5, equilibrate, and note the magnetization on the graph. Click the field to 3.5, let it run, and then click back down to 2.5. How does the magnetization compare for the two intervals at H=2.5? Why did we see hysteresis between 2.5 and 3.5 but not between 0 and 1?