We have just shipped Exsto 2.0. 
This is a massive update, not only have we introduced a Metal rendering engine for the first time to Exsto but also we made a lot of changes to focus the application on the core use-case of relaxation and creative exploration.
My wife (and co-author of exsto) was invited to attends Apple Entrepreneur Camp during this we had a lot of time with apple design, product and technical teams that lead us to the changes in 2.0. This is an outstanding program and for any developers out there able to apply I strongly suggest you do so. It was not just technical help but also higher level discussions we had that helped us figure out who Exsto was for and how/why they will use it.
So lets talk about Exsto a little:
Exsto is an iPad app that helps you to explore your creativity and discover the artist you never knew you were or could be. Relax, unwind, have fun and get a unique digital creation in the end.
Exsto takes an active part in your creative process by generating rich organic shapes with each stroke. You can guide it and lay out the shapes in an infinite space. Tune the noise level or the opacity of the strokes to get interesting effects.
Please take a look over out website: https://exsto.app
And we also launched on product hunt so any support and feedback there would be very helpful: Exsto - Discover the artist you never knew you were or could be | Product Hunt
You can find Exsto on the iPad App Store: Exsto on the App Store