When you start Portal on 3 or 5 apples, each piece of fruit takes you to its matching pair when eaten. Portal 5 apples small is chaos if you've ever played it before. There is a sneaky way that I like to begin whenever I play it though. At the start of the run, go behind the row of four fruits on either the top or bottom row and run right through all of them. It is a satisfying and easy way to start. Then, try and go for only one type of fruit/portal at a time and keep in mind that you may run into another portal as soon as you exit one so try and plan ahead before you accidentally run into a wall or another portal.