I did one in my gallery
Gallery at Splitcoaststampers
sizes of DS Paper
cut them at 3x3, 2 1/2, 2x2, 1 1/2
Fold them all as follows
fold in 1/2 open up
fold diagonal open
fold diagonal other way open up and lay flat
now fold in the sides so you have what looks like a triangle
fold left and right sides of the triangle in towards the middle
repeat with other pieces
stack on top of each other to form the tree