Colored lines and arrows, yellow spots.
The pink lines in the top picture show the positions of the atomic planes, perpendicular to the plane of the screen. Those planes consist of parallel lines, which are seen going from the observer towards the screen in the bottom picture. The direction of the normal N and the interplanar distance d are shown with pink arrows. The reciprocal lattice vector g associated with the above planes is shown as a dark-blue arrow, and the yellow spots show the locations of the reciprocal lattice points translated with this vector.
