JK flip flop 2 bit Counter

module JKflipflop(input [1:0] J, K, clock, output reg [1:0] Q, Q2, output Qb, Qb2);
    always @(posedge clock[0]) begin
        case ({J[0],K[0]})
            2'b00: Q <= Q;
            2'b01: Q <= 1'b0;
            2'b10: Q <= 1'b1;
            2'b11: Q <= !Q;
        endcase
    end
    assign Qb = !Q;

    always @(posedge clock[1]) begin
        case ({J[1],K[1]})
            2'b00: Q2 <= Q2;
            2'b01: Q2 <= 1'b0;
            2'b10: Q2 <= 1'b1;
            2'b11: Q2 <= !Q2;
        endcase
    end
    assign Qb2 = !Q2;
endmodule


module JKflipflopTB;
    reg [1:0] J, K, clock;
    integer h = 0;

    JKflipflop TB(.J(J), .K(K), .clock(clock), .Q(Q), .Q2(Q2), .Qb(Qb), .Qb2(Qb2));

    always #10 clock[0] = !clock[0];
    always #20 clock[1] = !clock[1];

    initial begin
        clock <= 0;

        repeat (4) begin
            {J[0], K[0]} <= h;
            {J[1], K[1]} <= h;
            h = h + 1;
            #10;
        end
    end
endmodule