LIT Distance max(|x−3|,|y−3|,|z−3|) is counted by a visit and by the closed forms 1 and (2k+1)³−(2k−1)³ for k = 1, 2, 3. Both give 1, 26, 98, 218, and those sum to 343.
AMBER Shell is the name of one distance class.
WALL The shells are not orbits of a physical body.