Figure 4. Subdomains of the small geometry for the development of the surface model. ( a , b ) Front view and back view; ( c , d ) ER rotated slightly; ( c ) webs unvisible, ribosomes open; ( d ) webs visible, ribosomes hidden. All surfaces together form the computation domain D . Middle blue: E , other colors: single web regions W i and ribosomal regions R i , i = 1,2, . . .