Second paragraph after the router code snippet reads:
Next, we need a subdirectory,
lib/pento_web/live/pento, to house the Pentominoes UI. Add a new file,lib/pento_web/live/game_live/game_live.ex, and define this live view:
The subdirectory stated in that paragraph most likely is lib/pento_web/live/game_live instead of lib/pento_web/live/pento.
Also, based on organizations made in previous chapters, the file probably should reside at lib/pento_web/live/game_live.ex instead of lib/pento_web/live/game_live/game_live.ex. For example, when building the survey live view, survey_live.ex resides in lib/pento_web/live/survey_live.ex instead of lib/pento_web/live/survey_live/survey_live.ex. If this suggestion were to be adopted, then the same updates should also be made in pages 365 and 366. By the way, a (code) comment on page 370 aligns with this organization convention, lib/pento_web/live/game_live.ex.