Another writer replied, "This is a glorious hack," and until that moment I hadn't thought of it as anything but kind of shameful—like, am I broken? Why can't I just work straight across the page? But process is process, and as long as you're not hurting anyone else, it doesn't matter.
Brackets are another of my longstanding systems, though these are less chaotic. If I'm not sure about a word or phrase, I'll frame it in curly brackets:
we {flail} for what to do
If I can think of several ways I might say it, I'll write each of those ways in adjacent sets of curly brackets:
thought I'd spend my life surviving {you} {my life}
If there's something I need to look up—say, for fact-checking or consistency with something established elsewhere in the story—I'll frame it in square brackets:
born in [1840].
This system lets me write first drafts without turning on the editorial brain—the editorial brain being, obviously, quite useful, but deadly to the flow state of early work. Later I can go back and fix things. If I've written lyrics without having a full melody, the bracketed alternatives are often what suggests some important change or rhythm. (In the top example, flail became fumble to suit the song's rhythm better. In the middle example, from a song I'm finishing up now, both versions of the line appear, framing the rest of the verses.)
Another favorite trick is to change the writing implement. Working in different colors can be useful for tracking the layers of revision, as well as just making certain ideas hit your eye differently. I resorted to crayon once, on a very stuck piece of fiction. (In retrospect, that one should have stayed stuck. I never even tried to publish it. But the crayons did unstick the writing for the day.)
I suppose all of these boil down to interacting with the writing as a physical, tactile thing. Maybe they work because we're all in the process of creating things out of nothing, and the physical form gives me a little more thinginess to work with? I don't know. I only know that keeping it too abstract, too digital, too deletable, does me no favors.