  Photo-polymerization of a reactive mesogen mixed with a mesogenic dimer,
shown to exhibit the twist-bend nematic phase ($N_{TB}$), reveals the complex
structure of the self-deformation patterns observed in planar cells. The
polymerized reactive mesogen retains the structure formed by liquid crystalline
molecules in the twist bend phase, thus enabling observation by Scanning
Electron Microscope (SEM). Hierarchical ordering scales from tens of nanometers
to micrometers are imaged in detail. Submicron features, anticipated from
earlier X-ray experiments, are visualized directly. In the self-deformation
stripes formed in the $N_{TB}$ phase, the average director field is found
tilted in the cell plane by an angle of up to 45$^{\circ}$ from the cell
rubbing direction. This tilting explains the sign inversion being observed in
the electro-optical studies.
