Acceleration for multiple stepper motors

#define DIR_PIN1          2
#define STEP_PIN1         3
#define ENABLE_PIN1       4
#define DIR_PIN2          5
#define STEP_PIN2         6
#define ENABLE_PIN2       7
#define DIR_PIN3          8
#define STEP_PIN3         9
#define ENABLE_PIN3       10
#define DIR_PIN4          11
#define STEP_PIN4         12
#define ENABLE_PIN4       13
#define DIR_PIN5          14
#define STEP_PIN5         15
#define ENABLE_PIN5       16

void setup() {
  pinMode(STEP_PIN1,   OUTPUT);
  pinMode(DIR_PIN1,    OUTPUT);
  pinMode(ENABLE_PIN1, OUTPUT);
  pinMode(STEP_PIN2,   OUTPUT);
  pinMode(DIR_PIN2,    OUTPUT);
  pinMode(ENABLE_PIN2, OUTPUT);
  pinMode(STEP_PIN3,   OUTPUT);
  pinMode(DIR_PIN3,    OUTPUT);
  pinMode(ENABLE_PIN3, OUTPUT);
  pinMode(STEP_PIN4,   OUTPUT);
  pinMode(DIR_PIN4,    OUTPUT);
  pinMode(ENABLE_PIN4, OUTPUT);
  pinMode(STEP_PIN5,   OUTPUT);
  pinMode(DIR_PIN5,    OUTPUT);
  pinMode(ENABLE_PIN5, OUTPUT);
}

#define STEPS 3000

void constantAccel() {
  int delays[STEPS];
  float angle = 6;
  float accel = 0.05;
  float c0 = 5000 * sqrt( 2 * angle / accel ) * 0.9000;
  float lastDelay = 0;
  int highSpeed = 100000;
  for (int i = 0; i < STEPS; i++) {
    float d = c0;
    if ( i > 0 )
      d = lastDelay - (2 * lastDelay) / (4 * i + 1);
    if ( d < highSpeed )
      d = highSpeed;
    delays[i] = d;
    lastDelay = d;
  }

  // use delays from the array, forward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN1, HIGH);
    delayMicroseconds( delays[i] );
    digitalWrite(STEP_PIN1, LOW);
  }

  // use delays from the array, backward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN1, HIGH);
    delayMicroseconds( delays[STEPS-i-1] );
    digitalWrite(STEP_PIN1, LOW);
  }

   // use delays from the array, forward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN2, HIGH);
    delayMicroseconds( delays[i] );
    digitalWrite(STEP_PIN2, LOW);
  }

  // use delays from the array, backward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN2, HIGH);
    delayMicroseconds( delays[STEPS-i-1] );
    digitalWrite(STEP_PIN2, LOW);
  }

   // use delays from the array, forward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN3, HIGH);
    delayMicroseconds( delays[i] );
    digitalWrite(STEP_PIN3, LOW);
  }

  // use delays from the array, backward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN3, HIGH);
    delayMicroseconds( delays[STEPS-i-1] );
    digitalWrite(STEP_PIN3, LOW);
  }
     // use delays from the array, forward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN4, HIGH);
    delayMicroseconds( delays[i] );
    digitalWrite(STEP_PIN4, LOW);
  }

  // use delays from the array, backward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN4, HIGH);
    delayMicroseconds( delays[STEPS-i-1] );
    digitalWrite(STEP_PIN4, LOW);
  }

   // use delays from the array, forward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN5, HIGH);
    delayMicroseconds( delays[i] );
    digitalWrite(STEP_PIN5, LOW);
  }

  // use delays from the array, backward
  for (int i = 0; i < STEPS; i++) {
    digitalWrite(STEP_PIN5, HIGH);
    delayMicroseconds( delays[STEPS-i-1] );
    digitalWrite(STEP_PIN5, LOW);
  }

}
void loop() {

  digitalWrite(DIR_PIN1, LOW);
  constantAccel();
  digitalWrite(DIR_PIN1, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN2, LOW);
  constantAccel();
  digitalWrite(DIR_PIN2, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN3, LOW);
  constantAccel();
  digitalWrite(DIR_PIN3, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN4, LOW);
  constantAccel();
  digitalWrite(DIR_PIN4, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN5, LOW);
  constantAccel();
  digitalWrite(DIR_PIN5, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN4, LOW);
  constantAccel();
  digitalWrite(DIR_PIN4, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN3, LOW);
  constantAccel();
  digitalWrite(DIR_PIN3, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN2, LOW);
  constantAccel();
  digitalWrite(DIR_PIN2, HIGH);
  constantAccel();
  digitalWrite(DIR_PIN1, LOW);
  constantAccel();
  digitalWrite(DIR_PIN1, HIGH);
  constantAccel();

  while (true);
}