眼电图

• 目(eye)RADICAL
• 艮(hard; stop)PHONO-SEMANTIC

Two eyes looking straight ahead, stubborn and resolute like the character for "firm."

• 曰(speak; bright cloud)ASSOCIATIVE
• 乚(lightning bolt; hook stroke (downward))ASSOCIATIVE

A flash of lightning bursts bright through the clouds—that is electricity itself!

• 囗(surround; square frame)RADICAL
• 冬(winter)PHONETIC

A map is a frame enclosing all regions of land, and when read closely sounds like "dong" (winter).