Norder to create space, escher created space by a. varying the sizes of the objects to create and illusion of depth. b. curving the forms of certain objects, such as the bookshelf and ceiling, in order to create the 3-dimensional sphere of the mirror. c. leading the eye to a primary focal point (the man), and the rounding everything out. d. including all of the above aspects.

In mathematics, space was created in order to do following tasks
 a. varying the sizes of the objects to create and illusion of depth.
 b. curving the forms of certain objects, such as the bookshelf and ceiling, in order to create the 3-dimensional sphere of the mirror.
 c. leading the eye to a primary focal point (the man), and the rounding everything out. 
so the answer is 
Escher created space by including all of the above aspects.