OTO - interactively produce visualized sounds app for iPhone and iPad

OTO, meaning SOUND(音) in Japanese, is an app made with the concept of "Pleasantly, interactively produce visualized sounds".

OTO is interactive.
In OTO, you can produce sound with your fingers.

OTO gives surprise and pleasantness.
In OTO, the size of the sound generated depending on the strength of your touch changes.

In OTO, the sound is visualized.
The size of the ball in the OTO represents the volume of the sound, and the color is attached along the synesthesia. Synesthesia is a sense of being able to embrace a different sensation to a certain senses, it is said that a very small number of people can embrace.
In OTO, the color is determined by the musical scale.