This is very very nice. when you are reading this, just keep this in the back of your mind - inside a cell- things are floating around constantly at a very high speed. those things do not have any crisp shape or boundary. so how do we tell them apart? they are phase separated. if you put an oil drop in water, you can still see the oil drop and water and tell them apart. that's a very high degree of phase separation. inside a cell the degree of phase separation is much lower. just putting this out here so that you could appreciate the complexity of the biology that you are reading. my wife educated me on this a bit.