iOS 7 has some cool features. One of them lets you create a custom vibration on your iPhone. Here’s how to do that.
Settings>Sounds>Ringtone>Vibration>Create New Vibration.
After that, you just tap on the screen to create your custom vibration.
You will see a progress bar. Tap to a rhythm of your choosing as the bar moves along. Then you can test it out and save it if you like it. Very cool.