Great article about the pleasing use of ‘3′ items, colors, fabrics etc. when decorating and designing.
The rule of three is a guideline that can be bent. Essentially, it was put into place so that people understand that a odd-number of items is more interesting than an even-number of items. So, yes, you can arrange 5 items or 9 items into a grouping and still achieve the same visual interest.
Then again there are people who absolutely love a symmetrical design layout and 2, 4, 6 will work better for their eye.