def even "Em n=2*m":
def odd "Em n=2*m+1":
def hp "($even(x) & $even(y)) |
($even(x) & $odd(y) &
(En (HS[?msd_4 n][x/2][(y-1)/2]=@1 & HS[?msd_4 n+1][x/2][(y+1)/2]=@1) |(HS[?msd_4 n][x/2][(y+1)/2]=@1 & HS[?msd_4 n+1][x/2][(y-1)/2]=@1)) | ($odd(x) & $even(y) &
(En (HS[?msd_4 n][(x-1)/2][y/2]=@1 & HS[?msd_4 n+1][(x+1)/2][y/2]=@1) |(HS[?msd_4 n][(x+1)/2][y/2]=@1 & HS[?msd_4 n+1][(x-1)/2][y/2]=@1))":