Do you know pattern password is not safe ?

Some phones are secured with pattern password that may like the picture in the side. This system of security is used in touch model devices. Do you know when pattern is made with your figures there will be a shade like pattern on the screen when you see the screen slant you could observe this others also can observe it so this type of security is not secure for touch screen. Be sure there are no marks in screen after your login. For password safety  change password ones or twice a month.