When you duplicate an object, the difference in position, scale, and rotation between the copy and the original is saved into the array tool. If you push the thumbstick on your left hand towards the array icon, another object will duplicate relative to the latest duplication.
This makes it possible to duplicate several objects evenly, or artistically.
DUPLICATE TOOL precedes this tutorial
Seen above on the right, is the array tool. This tool appears after you duplicate or move an object.
Seen above is selecting the lower corner snap point with the duplicate tool.
Seen above is moving the duplicate copy to the adjacent corners snap point.
Seen above is pressing the thumbstick left to use the array tool.