An idea for a multi-touch rhythm game

Here's an idea for a rhythm game for the iPhone that exploits the phone's multi-touch capabilities. 

Most rhythm games involve pressing or tapping on one of a fixed set of positions.  In Guitar Hero those positions are button positions, in Dance-Dance Revolution they're floor tiles, and so on. 

Touch-screens let the taps be anywhere on the screen.  Like in Elite Beat Agents on the DS where circular markers pop up on the screen showing you where to tap.   The sequence of places to tap usually follow a spatial pattern - eg in a line or an arc.  Following these patterns around adds some interest to the game.  It's more dynamic. Rhythm and movement work well together.  

On a multi-touch screen you could have a different style of game.  It could have the user make multiple touches at once, where the had to simultaneously tap points in a particular spatial pattern.  It might get them to simultaneously tap three points arranged in a line, then simultaneously tap four points arranged like the end points of a cross. The focus would be on the progression of spatial configurations.     

And just like how Elite Beat Agents also sometimes made the player slide the stylus along a path, this game could make the use simultaneously slide fingers across multiple paths.  For example, where their fingers start out at like the four corners of a box and have to simultaneously slide towards the box's center. 

I'm imagining something where it's like the players fingers are performing a dance. Something a bit like twister for your fingers, but rhythm elements to it. Maybe you could call it Finger Dance.

(this is the first time I've composed a post on my iPhone - nice use of a bus trip)