Set Width and Height up to 500, then press Build Grid. All tiles start white.

Select a color and click or drag to paint. If no color is selected, the brush paints black.

Select No color to use the eraser which paints white. Right click a color swatch to select the eraser.

Use Zoom. At 100 percent the short edge of the board fits all tiles. At 0 percent it shows about five tiles on the short edge.

Create Share Link to get a URL that encodes the current board. Send the link to reopen the same drawing and size.

Mobile: tap and drag to paint. Pinch zoom is not supported. Use the slider.