Again, Martha contributes to my life bringing joy and frustration. I learned how to do these snowflakes about 6 years ago. But they are always impressive and I love how they all turn out differently. Using 12-14 white paper lunch sacks, you trim about 1" off the bottom of the bag (while still folded flat.) Then you tape the sides of the bags together with three pieces of scotch tape, and do the same to the other side. Once all the bags are taped (creating a sort of lunch bag accordion) you may start cutting shapes out. I usually go 2-3 bags at a time, depending on how strong your scissors are. Cut in the spaces between the tape and when finished, bring the bookend bags around till they touch each other and the accordion forms a big, round snowflake. Tape those two bags together on each side, and display. Then cut those pieces again and fold back up to store.
(If you are interested in more detailed instructions, email me. This is involved..)