Notes
A small improvement to the previous poke - the "blood" accumulates once the bleed hits the bottom of the square.
I'm aware that this accumulation is unrealistic, though I think some observers might not realise it! The liquid's accumulation should be cumulative rather than independent. Right now it looks as though the liquids don't mix at all and are instead filling up the container (canvas) as if they were empty.
Since I wasn't trying to go for any effect in particular, I'm not going to try and keep a variable for making the liquid level rise cumulatively faster. I'm going to instead spend the time to read The Nature of Code and plot the next project in my mind!
TIL: You can add two more hex digits to a hex colour as the alpha values! e.g. #401999 => #40199970. The second hex colour has alpha of "70" or 70 percent opaque! This came in handy as I was passing a 6-hex-digit colour value down from the `drawBleed` function to the `drawAccumulation` function, and in the latter, I could just add two more digits to give it transparency.