The X Origin variable controls the point which an object is positioned by. By default the X Origin is Left. X Origin is shown visually as a white "X" in the editor.
ColoredRectangle with an X Origin of Left
Left
The following image shows a ColoredRectangle with its X Origin set to Left:
Colored Rectangle with X Origin set to Left
Center
The following image shows a ColoredRectangle with its X Origin set to Center:
ColoredRectangle with X Origin set to Center
Right
The following image shows a ColoredRectangle with its X Origin set to Right:
