Functions can take inputs (called arguments). This function has one argument n that tells how many corners are drawn. Can you draw a 5-pointed star? An 8-pointed star?
Add more arguments by declaring star = (n, m, s) ->. m can be the number multiplied by 360 when calculating the angle, and s could be the length of a side. Now can you draw an 8-pointed star?
Remember that you can use speed to see what your ideas do faster. Try speed 5 to watch the turtle travel more quickly, and speed Infinity to draw everything instantly.