According to this riddle, when should you stop at green and go at red?

Introduction / Context:
This riddle plays with our usual associations of the colours red and green. In traffic lights and many safety signs, green means go and red means stop. The riddle reverses this and asks when you should stop at green and go at red. Because this contradicts the traffic rule pattern, it forces you to look for another situation in everyday life where green and red have different meanings. The classic answer comes from food, specifically from eating a watermelon, and the puzzle tests whether you can break free from the traffic light association to see this alternative context.

Given Data / Assumptions:

- In traffic, green typically means go and red means stop. - The riddle asks for a situation where you should stop at green and go at red. - The options include a traffic signal, eating a watermelon, driving in a forest, playing a board game, and crossing a busy road. - We assume basic cultural knowledge of how watermelons look when cut.

Concept / Approach:
When you slice a watermelon, the outer rind is green and inedible or unpleasant to eat, while the inner flesh is red and tasty. The sensible way to eat watermelon is to stop at the green rind and not bite into it and to go at the red part by eating the juicy inside. This fits the phrasing stop at green and go at red perfectly. In contrast, at traffic signals and busy roads you must obey the standard rule go on green and stop on red, not the reversed version given by the riddle. Therefore, the food based interpretation is the correct one.

Step-by-Step Solution:
Step 1: Notice that the riddle deliberately inverts the well known traffic rule. Step 2: Recognise that if the riddle were about traffic, it would be unsafe and incorrect to stop at green and go at red. Step 3: Look for another situation where green and red appear together with opposite desirability. Step 4: Recall the appearance of a watermelon: green outer skin and red inner flesh. Step 5: When eating watermelon, you stop your teeth at the green rind and avoid chewing it. Step 6: You go ahead and eat the red flesh, which is the sweet, edible part. Step 7: This behaviour exactly matches stopping at green and going at red. Step 8: Among the options, only eating a watermelon fits this pattern naturally.

Verification / Alternative check:
Consider the alternative of a traffic signal. There, you must follow the official rule: go on green, prepare on amber, stop on red. Reversing this would not only be wrong but also dangerous. When crossing a busy road, you are again essentially following traffic light rules or looking for safe gaps in traffic, not the reversed colour rule. Driving through a forest and playing a board game do not have any standard stop at green, go at red behaviour associated with them. This makes those options weak or irrelevant. Only the watermelon example yields a clear and sensible interpretation that follows the colours and actions named in the riddle.

Why Other Options Are Wrong:
At a traffic signal or when crossing a road, the correct rule is go at green and stop at red, not the other way round. Driving in a forest does not usually involve any special rules about green or red colours. Playing a board game may use coloured pieces, but there is no universal stop at green, go at red rule across games. Therefore, these options do not match the precise colour and action pattern described by the riddle. Only eating a watermelon lines up with stop at the green rind and go at the red flesh in a natural and widely understood way.

Common Pitfalls:
Many learners initially focus on traffic lights because the words red and green almost automatically evoke that association. This is exactly what the puzzle exploits. The key to avoiding this trap is to remember that riddles often subvert expectations. Whenever a question seems to contradict a well known rule, it is a hint that you should switch contexts. Thinking of common objects that are green outside and red inside quickly suggests watermelon as the classic and satisfying solution.

Final Answer:
You should stop at green and go at red when you are eating a watermelon, stopping at the green rind and eating the red flesh.