always @(posedge clk) begin if (candraw) begin n_vga_blank <= 1'b0; // output a red rectangle in the middle of the screen for (i = 0; i < 16; i = i + 2) begin if (x > (i * 80) && x < ((i + 1) * 80)) begin red <= 10'b11_1111_1111; green <= 10'd0; blue <= 10'd0; // with a blue background end else begin red <= 10'd0; green <= 10'd0; blue <= 10'b11_1111_1111; end end end else begin // if we are not in the visible area, we must set the screen blank n_vga_blank <= 1'b1; end