So the strawberries are programmed that once collected they will appear in a random location but never at the same point as a "Rock". Same with the eggs, The idea is you ever want to avoid them as they will more often then not cause a game over, or collect them to get away from the cat. The actual speed of the strawberry boost should always be the same but would not be totally surprised if there is something in the code that mixes it up. Only had 4 days and we worked on the Friday and Monday in our full time jobs :).