Methods of using a shape-formable apparatus comprising locking sheets

A method of using a shape-formable apparatus, the method comprising:

• providing a shape-formable apparatus in a first state in which the apparatus is formable, the shape-formable apparatus comprising:
• an envelope defining a chamber, the envelope formed of a gas-impermeable material;
• a port positioned to fluidly couple the chamber with ambience;
• and
• at least two locking sheets positioned in the chamber in an at least partially overlapping configuration, wherein each locking sheet comprises a major surface, and wherein at least a portion of each locking sheet is patterned to include solid regions and open regions, the solid regions being movable with respect to one another within the major surface;
• forming the apparatus into a desired shape when the apparatus is in the first state;
• and
• reducing the pressure in the chamber to change the apparatus from the first state to a second state in which the apparatus has the desired shape and is substantially less formable than in the first state.