Apple Motion 3 - Manual (Page 757)

Chapter 9 Using the Replicator 757
When Spiral is the selected shape, parameters appear that allow you to define the
radius of the spiral, the number of twists and arms in the spiral, the number of points
(the location on the shape in which the element sits) per arm, as well as the origin of
the elements in the spiral (from the center outward, or from the edge inward).
Further, different parameters are also available depending on the selected arrangement
for the shape. In the following image, notice that the Columns, Rows, and Tile Offset
parameters are replaced with the Points and Offset parameters when the rectangle
arrangement is changed from Tile Fill to Outline.