The Rule of Odds says that an image should have an odd number of focal points or an even number of sub-focal points along with the main focal point. This is because, in general, people like to see an odd number of things (notice the Rule of Thirds, rather than the Rule of Halves or the Rule of Fourths).
In the image below, Alice is the main focal point, and her side-kicks are the scepter and the frog. Incidentally, the background also has three main elements: The brick wall, the wooden door, and the ground.
In the Martial landscape image created for the Rule of Thirds, there are three points of focus: The three rocks on the left, the one rock on the right, and the three strange black dust lines (tree-like structures) (which equals seven). There are also three levels of sand dunes, and the image is split into three main parts because of the two more obvious sand hills.