Dmitry Brant published an interactive scene in which the speed of light is 5 km/h. You are walking through the park in first person: WASD or arrows accelerate, the mouse turns its head, spacebar stops, R returns to the start. The L, G, C and B keys individually turn on and off the effects - length contraction, time dilation, aberration, Doppler shift (front blue, back red), relativistic brightening, Terrell rotation. The current speed and Lorentz factor are displayed on the screen. The post on Show HN collected 395 votes, the code is at GitHub.
Toggle switch for each effect
Physics here is more than a hundred years old, there is nothing new in it. The design of the interface is interesting: each input is placed on a separate key. While everything is turned on, the picture looks like a mess. When you turn off aberration, you see that it was precisely this that bent the edges of the world. You leave one Doppler - you understand where “the object has become shorter” ends and “the object has become a different color” begins.
The technique transfers to any work where you explain something through a screen.
Cost calculator: separate switches for each surcharge instead of one total. The client will see for himself which line makes the price.
Attribution panel: a toggle switch for each rule, rather than a drop-down list of three ready-made models. Otherwise, the debate “why the numbers are different” will be eternal, because there is nothing to compare.
Product demo: a button that turns off your feature and leaves everything else in place. The difference that a person saw for himself is worth more than a slide with percentages.
The second trick is to twist the constant, not the explanation. Special relativity seems abstract because of its scale: 300,000 km/s is nothing compared to a body. Lower the constant to walking speed and there's almost no need to explain further. The same move works when you show the load (“imagine there are three requests per second”) or the cost of an error in development.
Where are the borders
Intuition from a walk does not replace calculation. The ability to calculate Lorentz transformations cannot be taken out of the park; there is not a single formula there, and a person who “understood relativity through play” will struggle at the very first problem with numbers. For the team, this means a simple thing: such a thing is suitable as an entry into the topic for five minutes, and not as training.
And the colors in any such scene are the author's compromise. The real shift takes light beyond the visible range, and what the eye would not see at rest comes inside; What to draw on the screen at this moment is decided by the visualization developer, not the equation. If you show it to your colleagues, say it out loud, otherwise people will take away the beautiful picture as a fact.
Rule: when explaining a compound effect, give a toggle switch for each contribution instead of a paragraph of text. Open your demo page and count how many toggle switches there are.