Semi-golfed Canvas Setup
((
width = 200, height = 200,
cnv = document.body.appendChild(
Object.assign(
document.createElement('canvas'), {
width, height
})
),
c = cnv.getContext('2d'),
f = c.fillRect.bind(c),
C = _ => c.fillStyle = _) => {
C`gray`; f(0, 0, width, height);
C`blue`; f(10, 10, 100, 20);
})();