Pretty neat little website from Joan Perals, inspired by stuff like Lynn’s A Single Div. With multiple hard-stopbackground-image gradients, you don’t need extra HTML elements to draw shapes — you can draw as many shapes as you want on a single element. There is even a stacking order to work with. Drawing with backgrounds is certainly CSS trickery!
The site stores your drawing IDs in localStorage so you’ve got basic CRUD functionality right there. I bet the whole thing is a little hop away from being an offline PWA.