anchor.diff:                  [
                       {"Y1",
                           {'if',
  -                            lte({'#', TimeD}, 0),
  -                            "X1",
  +                            [{lte({'#', TimeD}, 0), "X1"}],
                               {'@',
                                   plus(
                                       plus({'@', "Y1", {t, [{XD, times({'#', XD}, 2)},
  
positive.code:                                 {t, [{TimeD, minus({'#', TimeD}, 1)}]}}}},
                      {"X1",
                          {'if',
                              tand(
                                  tand(gte({'#', XD}, 1), lte({'#', YD}, 1024)),
                                  tand(gte({'#', YD}, 1), lte({'#', YD}, 1024))),
                              {'#', XD},
                              1}}
                  ]},
              [{TimeD,2}, {XD,0}, {YD,0}]},
  
negative.code:                 }
              },
              {"B", {'if',
                      [{tand(gte({'#', SpaceD}, 1),
                             lte({'#', SpaceD}, 1024)),
                        {'#', SpaceD}}],
                      1
                  }
              }
  