Conway's game of life in fishshell

conways-game-of-life.fish

set DEAD "  "; set LIVE "🌱"; set wid 21; set hei 21
for cell in b(seq 2)r(seq $hei)c(seq $wid); set -g $cell $DEAD; end
set -g flip 1; set -g flop 2
function show_board
     for row in (seq $hei); for col in (seq $wid); set -l cell b{$flip}r{$row}c{$col}; echo -n $$cell
         end; echo; end; end
set b1r10c10 $LIVE; set b1r10c11 $LIVE; set b1r10c12 $LIVE;
set b1r11c10 $LIVE;                     set b1r11c12 $LIVE;
set b1r12c10 $LIVE; set b1r12c11 $LIVE; set b1r12c12 $LIVE;
while true
    show_board
    for row in (seq $hei); for col in (seq $wid);
            set count 0
            set dest b{$flop}r{$row}c{$col};
            if test $row -ne 1 -a $col -ne 1; set r (math $row -1); set c (math $col -1); set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# top left
            if test $row -ne 1; set r (math $row -1); set c $col; set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# top 
            if test $row -ne 1 -a $col -ne $wid; set r (math $row -1); set c (math $col +1); set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# top right
            if test $col -ne $wid; set r $row; set c (math $col +1); set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# right
            if test $row -ne $hei -a $col -ne $wid; set r (math $row +1); set c (math $col +1); set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# bottom right
            if test $row -ne $hei; set r (math $row +1); set c $col; set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# bottom
            if test $row -ne $hei -a $col -ne 1; set r (math $row +1); set c (math $col -1); set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# bottom left
            if test $col -ne 1; set r $row; set c (math $col -1); set src b{$flip}r{$r}c{$c};
                if test "$$src" = "$LIVE"; set count (math $count +1); end; end;# left
            set src b{$flip}r{$row}c{$col}
            if test "$$src" = "$LIVE" -a $count -gt 1 -a $count -lt 4; set $dest $LIVE; continue; end
            if test "$$src" = "$DEAD" -a $count = 3; set $dest $LIVE; continue; end
            set $dest $DEAD
         end; end
    if test $flip -eq 1; set flip 2; set flop 1; else; set flip 1; set flop 2; end
    string repeat -n (math $hei + 1) \x1B\x5B\x41
end