Even AI knows that line can't go down. Line does not go down. Line must not go down. Line only go up.
I'm not joking I generated 20 different images with this exact prompt and not one of them had the line go down. Turns out the tankies were wrong after all, line can only go up
If it's A₀-D₁-F₁-A₂, it's very low range, but a bizarre setup.
If you did A₁-D₂-F₂-A₃, that would be more guitar-like (and more impractical).
Standard four-string bass tuning is E₁-A₁-D₂-G₂.
I'd imagine, relative to standard tuning, you'd tune down the low E₁ to the A₀, tune down the A₁ to a D₁ (but both of those strings are like 7 semitones lmao, so you're begging for floppy strings there), tune up the D₂ to the F₂ (That's 3 semitones which is risky. If you ever have to tune up, 2 semitones would be the usual recommended max.), and tune up the G₂ to A, which, thankfully, is only 2 semitones.
It's workable, but you might need special gauge strings to do this really, weird hypothetical gimmick I pulled out of my ass because of a shitty AI image.
This is a dream that may stay a dream.
This is wonderful
It would probably make more sense with a five string bass. Then you would tune the B down to A, the E down to D, the A down to F, the D down to A, and I guess the G string down to C so you could get a major triad on the high strings. That way you avoid any neck strain with tuning up.