  If an inextensible thin sheet is adhered to a substrate with a negative
Gaussian curvature it will experience stress due to geometric frustration. We
analyze the consequences of such geometric frustration using analytic arguments
and numerical simulations. Both concentric wrinkles and eye-like folds are
shown to be compatible with negative curvatures. Which pattern will be realized
depends on the curvature of the substrate. We discuss both types of folding
patterns and determine the phase diagram governing their appearance.
