NO REVERSE direction in stepper.h

Hello,

I am testing the following code and the reverse direction command does not work. The motor continues in the same direction. I would appreciate any suggestions. Thank you!!

/*---------------------------------------------
February 13, 2017   Project for Daniel's lamp
Using an Arduino Uno to control a Velleman VMA401 5VDC stepper motor
controlled by a ULN2003 driver board. 
----------------------------------------------*/

#include <Stepper.h> //include the function library
#define STEPS 64 // 64 steps per rev
Stepper stepper1(STEPS, 8, 9, 10, 11); //create the stepper1
void setup() 
{
 Serial.begin(9600);      // initialize serial communication:  
}
void loop() 
{ 
  stepper1.setSpeed(120); //set speed to 10 rpm
  stepper1.step(640); //move 360 deg one direction
  delay(1000); //pause for effect
  stepper1.step(-640); //move 360 deg in the other direction DOES NOT CHANGE DIRECTION
  delay(1000); //pause
}

I would appreciate any suggestions.

Fix your stupid formatting. Right justification of code is stupid.