We show that the algorithm considered by Ishii [GAKUTO Internat. Ser. Math.
Sci. Appl. 5, Gakkotosho, Tokyo, 1995, pp. 111-127] and Ishii, Pires, and
Souganidis [J. Math. Soc. Japan, 50 (1999), pp. 267-308] can be applied to
motion by mean curvature with right-angle boundary condition.