Find all surface faces whose areas fall within a given range.

Input parameters:

1. Sf → Surface for face search.
2. A- → Lower limit for area. When the lower limit exceeds the upper limit, areas that fall between the limits are omitted instead.
3. A+ → Upper limit for area. When the upper limit is smaller than the lower limit, areas that fall between the limits are omitted instead.

Output parameters:

1. Fc → Found face surfaces.
2. Ix → Found face indices.