In reply to Jonshef:
If the contents are numbers (as in your example) you could do it by observing that each row follows a repeating 321321321 sequence and using formulas to reproduce this.
However, you can easily achieve the 'dropping down' effect by adding a formula refering to the cell up and to the left. For example, if you type 1,2 and 3 in cells A1,A2,A3 respectively, then in cell B2 you should type =A1
If you then use the black box dragging method to spread this formula down and then across you will get the dropping down effect. What you won't get is the end values 'looping back' to the top. So it will look like:
1
2 1
3 2 1
n 3 2
n n 3
('n' is just there because UKC won't let me have blank spaces)
Post edited at 13:22