This classic trick question says a red house is made of red bricks and a blue house is made of blue bricks. Then it asks: What is a greenhouse made of?
The answer is: glass.
A greenhouse is not simply a house that is green in color. It is a structure designed for growing plants by allowing sunlight in and trapping warmth. Greenhouses are traditionally made with large areas of glass or another transparent material.
The first two lines encourage you to follow a color pattern and answer “green bricks,” but that is the trap. The word “greenhouse” has its own meaning that has nothing to do with green-colored bricks.
Once you recognize that, the answer is clear.
