Here is a **clean blog excerpt** for the **Optical Illusions** article Ideal for Wix excerpt, Knowledge Hub preview, or SEO snippet Calm, human, student friendly --- Optical Illusions often begin with a moment of doubt. A picture seems to move, stretch, or change colour, even though nothing is actually changing. You look again, and your brain still insists something is happening. These illusions are not tricks or signs of weak eyesight. They reveal how the brain works fast,