Fold a piece of "strong", yellow paper or card in
half.
Draw, then cut along the outline and the line of the nose.
Overlap points "A" and "B" and stick or staple
them. Colour the nose black. Bring both points "C" together
and staple them.
Attach a band around the back of the mask in order to wear
it. Adjust it to see through the eyeholes.