Write a page. Send the page.
Write a short note. Press “Send this page” and you get a link. Whoever opens it watches your note being written, stroke by stroke, and then dry.
A letter
A letter for you.
Someone wrote this on the OAKGALL desk. Watch.

Your browser has 3D turned off (for example Lockdown Mode). This is what the desk looks like.
Where your letter is kept
Nowhere but the link. The strokes you write, the pen, the ink and the paper are packed into the part of the address after the #. Browsers do not send that part to any server, ours included.
Nothing is saved on our side, nobody can look your letter up, and we cannot read it. Lose the link and the letter is gone, like a page in the fire.