Before revision:  This can be expressed as the image of an `origami map' \varphi :D\to \boldsymbol  ^3 such that \Gamma is the singular set of \varphi , the word `origami' coming from the Japanese term for paper folding.
After revision:  This can be expressed as the image of an `origami map' \varphi :D\to \boldsymbol ^3 such that \Gamma is the singular set of \Phi , the word `origami' coming from the Japanese term for paper folding.