The mask pattern is half face front and back with middle fold making the bottom of the mask. If you want a two color mask, your right side will be one color and your left side will be another color if you cut two pieces of fabric of different colors in the pattern shape. In the picture below (and please pardon the wrinkles) I cut one piece of fabric in turquoise and the other in the batik fabric.
Attachment 24716
I hope this helps.
I've been toying with the idea of making a quilted mask using this pattern but so far am too lazy and exhausted from making masks to think about the how-to.