TC-11 is a fully programable multi-touch synthesizer for the iPad. This video demos some of the 64 included presets, and shows the multi-touch performance and device motion control.
TC-11 uses multi-touch control like no other app. The relationships between touches are controllers that drive synthesis. Since TC-11 is fully programable, any touch controller can change any synthesis parameter.
It's been a long road to finish the app, but it's live and out there. I hope you enjoy it!