I've noticed that (using a text object to show the values of each array value) when the grid is created on screen, it's done so top to bottom.
What I mean is, the first value of the array is the top left corner, the next value is the one UNDER that ... and so on, then it shifts to the next column and goes down again.
Here's a picture to explain a little. The numbers at the bottom is the value in each array element. They correspond to the image animation frame to give different colours. They match up with the order going DOWN the grid, then across one and down again.
<img src="http://s17.postimage.org/i3jmu5gpr/path.png" border="0" />
I was under the impression than arrays shift left to right, then down to the next row ... etc. Anyone know why it's going the other way? I think I've been staring at it for too long and can't see the woods for the trees.