The Miura-ori is a method for folding up a sheet such that it can be opened or closed in one smooth motion. A Miura sheet has only one degree of freedom, and can be thought of as having only two states: fully open, or fully closed. Since reversing one fold in the sheet (that is, making a “mountain” into a “valley”) requires reversing all of the adjacent folds as well, the Miura sheet feels as though it has a memory, and is very resistant to deformation.