A long time ago, I learned how to make 2D paper snowflakes in elementary school art class.  A square sheet of paper was first folded diagonally to form a triangle (a rectangle sheet could be made square by folding a long side against a short side and trimming of the extended flap).  The triangle was then folded in half to form a smaller triangle.  The smaller triangle was then folded into thirds (one flap forward and one flap backward) creating a tall thin triangle with the base corners extended beyond the center of the base.  The two ends were then trimmed to form a triangle with a flat base. 

Various shapes were carefully sniped out along both long edges so as not to destroy the basic triangle.  When unfolded, the end result was a six sided 2D snowflake made out of paper.  For a visual, visit 2D Paper Snowflake.  That was a long time ago.  Truth is I could not remember the entire proper folding sequence; therefore, looked it up on the internet. 

It was during that search that I discovered a site that showed how to create 3D snowflakes.  A 14 step process that I am not going to even try to describe here because visuals are needed.  Instead, I will just point to 3D Paper Snowflake and let them show how it is done.  While snowflakes are generally associated with winter, the paper snowflakes can be crafted year around.