My grade in primary school was shown one or two videos from a specific educational videoseries. I have to assume based on the visuals it was on the topic of scale or geometry or basic trigonometry. I have a vague memory of watching one video in something like social studies class but not sure.

It had a very distinc style:

• Barely to none dialogue or voice at all. Even besides that the audio was not any natural noise that would be captured by a microphone at the time of filming.
• Most of it was cold and monochrome and often dark. I remember there often being a flat solid grey background with barely any depth, but it wasnt a greenscreen edited in post..
• There was a presenter (not always the same person but one at a time). The facial expression was almost always just a neutral resting/stoneface and body language mostly matched that. Their gaze was mostly an empty or trance-like stare. They looked aware of their viewer but didnt really acknowledge them. The clothing varied but was also plain and monochrome but a mix of a darker and lighter than the background.
• The presenter would, in silence, make gestures in the air. In post these gestures are overlaid with a flat 2d shape or vector graphic being actively drawn and manipulated. These shapes were just thin white outlines, almost as if they were glowing but with neglible bloom. Sometimes these object would feel motiontracked to the presenter and sometimes anchored to a static point in space.
• There was sometimes a separation in the video as some form of intermission. I remember it being a black screen with white symbols on it. there were also smaller breaks where a presenter would pose in some way as if preparing for a photo session. This sometimes involved furniture like a small stool.
• When the floating objects were interacted with artificial notes or hums were heard. There was a droning background noise sometimes. During the intermission and small breaks there would be a very short 'melody' of a percussion sound repeating.

This videoseries was clearly meant for those with loss of hearing. It had a huge reliance on visual learning trough the drawn shapes and its otherwise muted asthetic was probably intended to distract as little as possible from that. The added sounds and mixing were probably just there to help the whole thing still feel tactile and engaging for those outside the target audience.