The buttons at bottom give you higher iterations; click the “edit” button to change the seed shape. When editing click and drag the endpoints of any line. Then click the “finish” button at bottom to see the results.

In edit you can double-click on the middle of a line to split it into two. Select an endpoint and press the "delete" button on your keyboard to delete a line.

At the bottom of the edit page are colored orientation lines; if you click on one of those and then click on a line in the seed shape it will change to that orientation. There are also invisible lines and non-replicating lines.

You can clear the editing page to make your own seed shape. Double-click on the last point or click the "finish" button to get the applet to add in the “baseline” (which is a dashed line that goes between the first and last points). The baseline establishes the scale for the replications. Its often a good idea to make the last two lines attached to the baseline invisible, so you can change the baseline indepedently of the rest of the seed shape.