Draw a cube in canvas #litecanvas

code.js

litecanvas()

function init () {
  loadScript('https://unpkg.com/@litecanvas/plugin-more-shapes/dist/dist.js', (res) => {
    if (res) plugin(pluginMoreShapes)
  })

  size = 100
  x = WIDTH/2 - size/2
  y = HEIGHT/2 - size/2
  colors = [4,5,6]
}

function update (dt) {
  if (LOADING) return
}

function draw () {
  if (LOADING) return
  cls(0)
  polfill(
    [
      x, y,
      x + size, y,
      x + size, y + size,
      x, y + size,
    ],
    colors[0]
  )

  polfill(
    [
      x, y,
      x + size/2, y - size/2,
      x + size/2 + size, y - size/2,
      x + size, y,
    ],
    colors[1]
  )

  polfill(
    [
      x + size, y,
      x + size + size/2, y - size/2,
      x + size/2 + size, y - size/2 + size,
      x + size, y + size,
    ],
    colors[2]
  )
}

Live demo: https://litecanvas.js.org?c=eJydkF1LwzAUhu%2F7K87dUmyXrqgXwkRhsg38uNjAi7GL0qZbNEtCkqpT%2Bt9NUztaXVG8SU7e85HnPYwakib8JdHI97y84KmhggPl1ADy4cMDYCLJFqmi0qDB1hipLzAuuHzeDFOxw1fsMAFLVmwoD3dCkVBvE0k0zqg27hg%2B6UEASBHtw%2FjSDQag%2BZdSd6L6urP9C9fu26rScgFo%2Bk5gDKMoso83Gz3OJ8sZjiF0KRxbeW%2Fl2c18Olt29VQwobRNrk6Ds%2BB87ZUtp4XMEkMAZaZ2WyHdPlxP5vdTHxQxheKd%2Bkwlr81mjtXa75hGUUUuBcspY8hZXbnTsgewD5oYThzlcamJWo0daV1ftbtVtLYvt6o%2Ff4vjamSzqJ%2FZFkpf0WFqF2b0C0y%2F7%2F%2BjfV9XzyK7oHENWnqfAy3Ppg%3D%3D