P 3,NR.143*CZECH*
LATT -1
SYMM -Y,X-Y,Z
SYMM Y-X,-X,Z
    0 .6666 / 0 .6666 / 0 1
    SONDER: X .LE. (1+Y)/2
    SONDER: Y .LE. MIN. (1-X,(1+X)/2)
    P 3,NR.143*CZECH*