procedure main()
   every j := 1 to 4 do
    { i:=0
      (i<-j) > 2    #NB. i<-j undone if j>2 fails, if j<=2, and i<-j resumed.
      write("i=",i, " j=",j)
    }
end

# Reversible Assignment <-, from 11.8.2 p120 Icon Programming Language 1983.