fun print_single (cell: bool): void = do
    case cell of
        | true -> @write("█");
        | else @write(" ");
    end;
end;

fun print_vec (state: vec_bool) (length: int) (curr: int): void = do
    if curr == length then @write(""); else
        do
            @get(state, curr) |> print_single(_);
            print_vec(state, length, curr + 1);
        end; 
    end;
end;

fun cell_merger (a: bool) (b: bool) (c: bool): bool = do
    if a then
        if b then
            if c then
                return false;
            else
                return true;
            end;
        else
            if c then
                return true;
            else
                return false;
            end;
        end;
    else
        if b then
            if c then
                return true;
            else
                return true;
            end;
        else
            if c then
                return true;
            else
                return false;
            end;
        end;
    end;
end;

fun next (state: vec_bool) (pointer: int): bool = do
    case pointer of
        | 0 -> do
                let a: bool = false;
                let b: bool = @get(state, 1);
                let c: bool = @get(state, 2);
                return cell_merger(a, b, c);
            end; 
        | 1 -> do
                let a: bool = @get(state, 0);
                let b: bool = @get(state, 1);
                let c: bool = @get(state, 2);
                return cell_merger(a, b, c);
            end;
        | 2 -> do
                let a: bool = @get(state, 1);
                let b: bool = @get(state, 2);
                let c: bool = @get(state, 3);
                return cell_merger(a, b, c);
            end;
        | 3 -> do
                let a: bool = @get(state, 2);
                let b: bool = @get(state, 3);
                let c: bool = @get(state, 4);
                return cell_merger(a, b, c);
            end;
        | 4 -> do
                let a: bool = @get(state, 3);
                let b: bool = @get(state, 4);
                let c: bool = @get(state, 5);
                return cell_merger(a, b, c);
            end;
        | 5 -> do
                return true;
            end;
        | else return false;
    end;
end;

fun iter (state: vec_bool) (for: int) (curr: int): void = do
    if curr == for then
        @write("");
    else
        do
            let next_state: vec_bool = [
                next(state, 0),
                next(state, 1),
                next(state, 2),
                next(state, 3),
                next(state, 4),
                next(state, 5)
            ];

            print_vec(next_state, 6, 0);
            @write("\n");
            iter(next_state, for, curr + 1);
        end;
    end;
end;

fun main: void = do
    let vec: vec_bool = [false, false, false, false, false, true];
    print_vec(vec, 6, 0);
    @write("\n");

    iter(vec, 20, 0);
end;