Welcome to Android Central! If you're in Download Mode, you can power off from there and power back on. If the battery is removable, just pull the battery for 10 seconds, then reinsert it and power on. If the battery isn't removable, then press and hold Power and Vol Down for about 10-15 seconds until the phone shuts off.
But this won't help much if you can't remember the pattern you created. If the phone doesn't prompt you for your Google account and password after multiple failed attempts, then you might have to do a factory reset from the Recovery Menu. This will still require you to enter your Google account and password after the reset in order to proceed, so hopefully you haven't forgotten that.