begin const x=1; if x==2 then x:=x+1; if x==9 then x:=x-1; if x==8 then x:=x+2; case x>1 --> x:=x+1; x==1 --> x:=x-1; x<1 --> x:=7; end_case y:=x; if x==2 then x:=x+1; if y>9 then x:=x-1; end