code: function circle (params) {
    const defaults = {
      r: 1,
      fn: 32,
      center: false
    }
    let {r, fn, center} = Object.assign({}, defaults, params)
    if (params && !params.r && !params.fn && !params.center) r = params
    let offset = center === true ? [0, 0] : [r, r]
    return CAG.circle({center: offset, radius: r, resolution: fn})
  }
docs: Construct a circle
  @param {Object} [options] - options for construction
  @param {Float} [options.r=1] - radius of the circle
  @param {Integer} [options.fn=32] - segments of circle (ie quality/ resolution)
  @param {Boolean} [options.center=true] - wether to center the circle or not
  @returns {CAG} new circle
  
  @example
  let circle1 = circle({
  r: 10
  })