Transverse sections of bare region of rat SOL and EDL revealing lattice type. (A) SOL shows triangular filament profiles pointing in approximately the same direction along all three lattice planes (arrows) and within a hexagon (circle). This suggests a simple lattice. (B) EDL shows triangular profiles with variable orientations, which are analyzed below. (C–F) SOL and EDL sections at higher magnification analyzed by projection matching. (C and E) Raw images with superposed white triangles representing orientation determined by projection matching (see text). (D and F) Triangles extracted from C and E reveal orientations most clearly. (D) Triangles with similar orientations in all three planes (red rectangles) and in hexagon (circle). (F) Triangles with varying orientations, mostly following the no-three-alike rule. Scale bars, 200 nm (A and B); 100 nm (C–F).