This application is helpfull for absolute pitch training by playing 12 tones with its name utterance and color.
"C" means Color, Circle, Cycle and C hex(=12).
To learn each scale tone, the app play four sequence patterns.
1. Major Scale
2. Miner Scale
3. Cyclic chord arpeggio
4. Circle of 5th secuence
You can change the color, tone name, voice and instrument etc. in iOS settings.