LET ZU1 = 0
@IF 2 0 LET ZU1 = _2
LET ZSD1 = 1
@IF 3 0 LET ZSD2 = _3
LET ZU2 = 0
@IF 4 0 LET ZU2 = _4
LET ZSD2 = 1
@IF 5 0 LET ZSD2 = _5
LET ZP = 0.5
@IF 6 0 LET ZP = _6
