D3 version 4 and the HTML5 Canvas API draw animated, colored grids of cells whose count is set by user input between 1 and 10,000. The code binds data to custom DOM elements, using transitions to animate cell size and fillStyle, then a d3.timer repeatedly invokes a draw function that clears and repaints the canvas. A d3.scaleSequential with d3.interpolateSpectral maps data values to colors.