Comment by bonzog

The three-lamp triangle system is clever and reminds me of the Eye Reference Indicator in an aircraft cockpit. You adjust your seat so that the three balls are aligned in a specified way. [1]

This is important in providing the correct visual reference out the window, as that in turn affects the pilot's perspective of other external cues.

[1] https://safetyfirst.airbus.com/are-you-properly-seated/