(Strip Number 6747, Original Publication Date, 2 July 2018)
Panel 1: We find ourselves watching Liz see what Dawn is up to today. What Dawn is up to is painting with watercolors. As she sketches the landscape, Liz reminds us what her last name is by just up and helping herself to the tumbler of mystery purple liquid Dawn has and tells her that the grape juice she has tastes awful. Dawn knows this.
Panel 2: Liz blanches when Dawn explains that it's actually her paint water. As this happens, a garbage person in a basement says evil words about how it's a shame that the lesson about being a rude Rhoda didn't stick.
Panel 3: The strip proper begins with Liz asking Dawn what she's painting. Dawn says that she's painting a landscape.
Panel 4: Liz then sets things in motion by confusing Dawn AND us by declaring that there's no "M-birds" in the picture. Since she's never heard the expression before, Dawn asks her what she means. (She should also ask if Liz has suddenly mutated into a forty year old woman who doesn't know how real children speak because she's spent most of her life holed up in her den letting her mother in law raise her kids for her.)
Panel 5: Since Liz IS a Patterson, she thinks that repeating an unfamiliar word will make it as obvious to Dawn as it is to her but, as Dawn's confusion attests, it does not.
Panel 6: Since Dawn seems to behave as if she doesn't know what the funny word means, Liz will indulge her pretense that she has no idea what Liz is talking about and proceeds to show her what she means.
Panel 7: When Liz tells her "There! See?", Dawn says "Oh" when she finally sees what Liz means by that confusing word.
Panel 8: As she saunters off and declares that you can't have a landscape without M-birds, we look at things from over Dawn's shoulder and see that she has painted birds in flight that look like a lower-case letter M. I'm not sure if Dawn's smile is in gratitude or if she's trying to put a nice face on having her picture desecrated by clouds that say "MMMMMMMMM!!!!!"
Summary: Liz never managed to outgrow the habit of assuming that a person she's talking to knows the same things she does. Today, it results in her thinking that she's slightly smarter than the person she's confusing. Tomorrow, it results in her thinking that someone is using her jealousy powers to make her fall on her fat ass. Also, as aprilp_katje said, Liz is talking like a sitcom monster child instead of a real person again.