module validation(
output a
);


reg a1 = 0;

assign a = a1;

integer counter = 0;


while(1) // Infinite While Loop

begin

counter <= counter + 1; //The counter goes up.

if(counter == 0)begin

a1 <= ~a1; //If the counter reaches 1000, toggle the output.

counter <= 1000; // Resetting the counter.

end

end


endmodule