Alien Sound Drawing allows the user to draw on the screen, while drawing the app generates sound waves and these sound waves can be used by another IOS device with this app to rebuild the draw. The communication channel is sound. Pay attention, while you draw, do it slowly if you want good results and silence is required, this app does not work in noisy places.
You can save your draw in the device and play it later, if another device with this app is listening, it will reproduce your draw. You can have infinite listening devices.