LeftHanded

There are various music apps for iOS but this app has an unique feature which they do not have. Please see this app's keyboard in the screen shots. Left and right are reversed.

It may be better suited to left-handed people. Also, it might be a new discovery for right-handed people.

It includes the same synthesizer engine as bs-16i (single part only). It supports all standard MIDI messages, using pre-installed GeneralUser GS SoftSynth v1.44.sf2 (S. Christian Collins), you can play various instruments.

Moreover, this application supports Core MIDI output, so your play can be sent to other apps, and external MIDI hardware using Core MIDI compatible Interface like as IK Multimedia iRig MIDI, iRig KEYS, YAMAHA iMX-1, LINE6 MIDI Mobilizer 2, Apple Camera Connection Kit with USB MIDI Interface.