code: function (otherCsg, csg) {
    if ((otherCsg.polygons.length === 0) || (csg.polygons.length === 0)) {
      return false
    } else {
      let mybounds = bounds(otherCsg)
      let otherbounds = bounds(csg)
      if (mybounds[1].x < otherbounds[0].x) return false
      if (mybounds[0].x > otherbounds[1].x) return false
      if (mybounds[1].y < otherbounds[0].y) return false
      if (mybounds[0].y > otherbounds[1].y) return false
      if (mybounds[1].z < otherbounds[0].z) return false
      if (mybounds[0].z > otherbounds[1].z) return false
      return true
    }
  }
docs: returns true if there is a possibility that the two solids overlap
  returns false if we can be sure that they do not overlap
  NOTE: this is critical as it is used in UNIONs
  @param  {CSG} csg