re: 20% black corners etc.
ORR use the CAPTCHA tactic! Simply "smudge" sensitive words/topics/symbols, or all-out cut and move portions by 20%!
Use your heads anons, the black corners suggestion from Q was just to get us started on trying different tactics to avoid censor algos! Opacity and color doesn't do much either. We must rearrange or change over 20% of the actual pixels.
Perfect example pic related.