Ensō is a writing tool that helps you enter a state of flow.
Basically, you write, and Ensō only allows you to see the most recent lines you've typed. The previous words become invisible so you're not tempted go back and make changes. The Backspace button on your keyboard works, but the arrows don't. So, if you are tempted to go back, you're deleting, not moving the cursor to make changes.
Done writing? Hit the download button in the top left of the screen and a txt file of what you've written drops into your documents folder. Easy-peasy.
It's free on the web, or there's a pay-for-it app. The only thing missing is a Dark Mode.