This is a kind of sketchpad written in JavaScript.
Try it out here!
Specifics:
- The sketchpad is initially set up as a grid with 16x16 squares
- As the user hovers his mouse over each square, it changes color, leaving a (pixelated) trail through the grid like a pen would
- The grid and squares are styled using flexbox. Resizing the window horizontally resizes everything responsively
- The user can pick a new color, clear the grid, or change the dimensions by specifying a number of squares per side.
From The Odin Project's curriculum.