Question

glass cup puzzle
can only move one glass
full empty full empty full empty

Explanation:

The goal is to alternate full and empty glasses. By moving only one glass (the 2nd full one), you pour its contents into the 5th empty glass, creating the alternating sequence: full, empty, full, empty, full, empty without needing to reposition more than one glass physically.

Answer:

Pour the water from the 2nd full glass (top row, left to right) into the 5th empty glass (top row, left to right), then return the now-empty 2nd glass to its original position.