R 3 C,NR.161*MJ*
LATT    -3
SYMM    -Y,  X-Y,     Z
SYMM   Y-X,   -X,     Z
SYMM    -Y,   -X, .5+Z
SYMM     X,  X-Y, .5+Z
SYMM   Y-X,    Y, .5+Z 
    0 .6666 / 0 .6666 / 0 .1666
    SONDER: X .LE. (1+Y)/2
    SONDER: Y .LE. MIN. (1-X,(1+X)/2)
    R 3 C,NR.161*MJ*