MatheMagician: If you look into the code, that part is easy. ^^; I did not do that because that is not part of the subjects I would like the students to learn about. Students can does that themselves, if they like.

The crab's life is harder when the world is smaller. 場景變小，遊戲更難玩了。 Also, you have a cool way of using random numbers. 亂數的用法很酷喔！ ^_*'

The mushroom is so cool! It moves the crab 150 steps forward. 蘑菇好酷！吃了蘑菇，螃蟹會瞬間往前走150步。 Maybe we could directly put the crab randomly when it eats a mushroom? 也許也可以吃了蘑菇，就瞬間移動到亂數地點？

This is cool. And you could have, 1. Randomly placed the worms. 2. Randomly placed the lobster. 3. Randomly placed the crab.