Array Duplication: Rectangular Duplication and Circular Duplication.
The array duplication function, modify the parameters of rectangular and circular duplication, dynamicly display the updated results.
You can control the copies in Rectanular Array by dragging the Spacing / Copies control point at the upper right corner of the bounding box. Drag the point to adjust the number of copies, keeping the spacing unchanged. Hold Ctrl and drag to adjust the spacing, keeping the number of copies unchanged.