Blink problem

Hi. newbie to Arduino I bought the ONE and lcd keypad shield.
Trying to make someting I have two leds (red and green) and for a stupid test I modified the blink example
/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain.
*/

void setup() {
// initialize the digital pin as an output.
// Pin 13 has an LED connected on most Arduino boards:
pinMode(9, OUTPUT);
pinMode(12, OUTPUT);
}

void loop() {
digitalWrite(9, HIGH); // set the LED
digitalWrite(12, LOW);
delay(1000); // wait for a second
digitalWrite(9, LOW); // set the LED off
digitalWrite(12, HIGH);
delay(1000); // wait for a second
}
The problem is that leds blink all together...Where is the problem???? I also tryed to compile with an old software version but it is the same

How did you connect them?

Gnd is common with a resistor and one to pin 9 and other to pin 12.
I also notice that if i dont use one of the two led and tell the arduino to blink pin 13 and other pin, if i use only the led on the board the leds blinkright...if i connect the normal led on the pin 13 also , the two leds blink as one....

Gnd is common with a resistor and one to pin 9 and other to pin 12.

A picture is going to be necessary, because this description is not any where near adequate.

"Ground is common with a resistor" is nonsense. We expected that you connected one LED to pin 9 and the other end to pin 12. But, which leg of the LED is connected to the pin? Where is the other leg connected?

I have not an image at the moment

I'll try to explain better.

pin 9 -------------------
led green
gnd------resistor--------
led red
pin12 --------------------

I think is clear.
Thank you

(disclaimer: sw guy speaking here)

That way the current flowing through the resistor is different if one or both leds are on. And that's a Bad Thing (tm), as the v=ri across R will vary too. Is this correct ?

It should be like this:

pin 9 -----resistor-------- green LED -------- ground

pin12 -----resistor-------- red LED ------------ground

Be sure you have the LED anode (long pin) to the resistor, and the cathode (flat spot) to ground.