Limited experience bubble.
Forgotten information bubble. Learned but now forgotten.
Ego bubble / egoism.
Reminder and reminding.
Turbolift Star Trek - goes in many directions, not just Elevator up and down.
Jacob's Ladder. Staairway to Heaven.
++ Also underground into levels of Hell.
Also sideways, geographic aspects of language dispersion, city accent, national languages.
++ Metaphor languages. Quran vs. Upaanishads vs. Navajo Pollen Path.