Here is an overview of the mask-making process.
   

All the pieces are cut from the Wonderflex© material and laid out before starting the shaping and sculpting.
A generic face-form which I sculpted from plaster is covered with foil to prevent sticking.
A heat gun is used to soften the material and shape it. As it cools, Wonderflex© hardens to a higher rigidity than in its original state, yet retains some flexibility.
A second layer is fused onto the first one, and each leaf is shaped as needed.
Same as above, side view.
Sculpting is complete, eyes have been cut out, ready for finishing.
Many coats of gesso and acrylic paints later...
The inside is lined with soft acrylic felt for comfort, and fitted with a cord and cord-lock.