code: function(m){
          return new Vec2(
              this.x*m[0][0]+this.y*m[0][1],
              this.x*m[1][0]+this.y*m[1][1]
          );
      }
docs: Creates a new vector converting the vector to a new coordinate frame at the same origin.
  @memberof Vec2#
  @param {Array} m - Coordinate system matrix of the form [[Xx,Xy],[Yx,Yy]]
  @returns {Vec2}