this effect is accomplished by alternating these two grayscale ramps in a checker pattern btw:
"▁▂▃▄▅▆▇█"
"▏▎▍▌▋▊▉█"

@aeva Thanks for reminding me how much I hate whatever font is providing those box-drawing characters.

@MrDOS oh noo wtf lol

@aeva @MrDOS it's similar for me. Would be interested to know if there's a system that commonly displays all of these using the same font (assuming even that there is a font with them all on and it's installed).