If you are using a mouse or a trackpad that has multi-touch enabled then you likely know that doing a two-fingered swipe will scroll the window into the direction that the swipe occurred. But did you know that there is also a four-fingered swipe? If you swipe four fingers to the right or left then you will invoke an application selection screen, similar to the selection screen you see with Command-Tab. You can then use the arrow keys to switch between foreground applications. If you use the four fingered swipe in a downward direction you will bring up the all windows Expose screen. If you use the four fingered swipe…