I tried to do this many years ago. My data represented the number of
students enrolled at a college, split by gender and by age - it
occurred to me that by plotting male as -ve and femail as +ve and age
(in 5-year bands) on the y-axis, and by colouring the "branches" (on a
bar-graph) green, then the result may look like a xmas tree (it was in
November/December that I was doing this, so there was the seasonal
element). In the end it didn't look too much like a Christmas tree as
it was much broader in the lower age bands (19-24, 25-29), but everyone
referred to them as Pete's Xmas tree graphs.

Hope this helps you.

Pete

Using the DATEDIF function, I find you have 353 days to complete this task.
On graph paper draw an Christmas tree.
Work out the (x,y) values of the points and list them on the worksheet going
around the tree (either direction)
Draw an XY chart from the data