"I have a stack of five cubes. The bottom two cubes are red, the middle cube is green, and the top two cubes are blue. I remove the top two cubes. What color is the remaining cube in the middle of the stack?"

Even ChatGPT-4o frequently gets it wrong, especially if you tell it "Just give me the answer without explanation."

o3 gets this one right:

"After taking away the two blue cubes, three cubes remain—in order from bottom to top: 1. Red 2. Red 3. Green

With three cubes, the cube in the central (second) position is red."