It's less that I don't understand how to avoid damage and more I just find it somewhat challenging. The one that immediately comes to mind is the random spears with one of each color coming from a random direction. I often fail to spot the next one in time.
I usually get somewhat lost when all four colors are on the screen as well, but I think that's more my lack of exposure to it than anything else. All four usually don't appear until the final few attacks so it makes it a little difficult to practice.
Honestly, all of the attacks are really well balanced and defiantly avoidable. I feel like there are probably some I haven't seen yet, or at least a variation of one. I know I've only seen the 3x3 spear box once, which threw me off for a bit when it happened.