The realization of the game box

1) in the frame of 800 * 800 every 2 SEC position randomly generated little squares, wide high for 5 px, color is green, with the increase of the survival time, wide high increases gradually, up to 10 px, the color gradually turn red;
2) small squares in the box moving randomly, each moving distance within the 5 px, cannot be removed from outside the box;
3) use the mouse to click any one square, the square disappear;
4) if the square box number less than 20, the newly generated a,