Omar is pointing at an important point about arrays. With an array every element is seen as being logically identical to every other element. Consequently, the only thing that is (or can be) different from one value to the next is the value. That is why Omar's solution works: it depends on a changing value; and your original idea does not: it depends on a changing property.
However it's not just color. No property can be different between elements.
This all ties in when deciding what datatypes to use. Many people think the decision between array and cluster is simply a matter of the item (or element) datatypes. But its more of a matter of the logical meaning of the values. You could put the height, length, breadth and mass of a box in an array because all the numbers can be represented as floating-point values. But this would be incorrect because the values logically represent different things. In this case, the proper datastructure would be a cluster.
And this difference can have practical implications: like for instance if I need to extract the length I need to remember that it is element 2 -- or is it 1... See what I mean?
Mike...
