fn cube(length, center) {
  l = length/2
  x = center[0]
  y = center[1]
  p0 = [-l + x, -l + y]
  p1 = [-l + x,  l + y]
  p2 = [ l + x,  l + y]
  p3 = [ l + x, -l + y]

  return startSketchOn(XY)
  |> startProfile(at = p0)
  |> line(endAbsolute = p1)
  |> line(endAbsolute = p2)
  |> line(endAbsolute = p3)
  |> line(endAbsolute = p0)
  |> close()
  |> extrude(length = length)
}

myCube = cube(length=40, center=[0,0])