attiny85 fader code, how do i speed it up?

ok so i have programs my attiny85 to fader a RGB led, but i want it to fade through the colors faster. How can i do thi in the code????

// attiny85 RGB led rainbow fade

const int redPin = 3;  
const int grnPin = 4;  
const int bluPin = 1; 


void setup()
{
  pinMode(redPin, OUTPUT);     
  pinMode(grnPin, OUTPUT);     
  pinMode(bluPin, OUTPUT);     
}

void loop()
{
redtoyellow();
yellowtogreen();
greentocyan();
cyantoblue();
bluetomajenta();
majenatored();
}


void redtoyellow()
{
   digitalWrite(redPin, HIGH);
   digitalWrite(bluPin, LOW);

  // fade up green
  for(byte i=1; i<100; i++) {
    byte on  = i;
    byte off = 100-on;
    for( byte a=0; a<100; a++ ) {
      digitalWrite(grnPin, HIGH);
      delayMicroseconds(on);
      digitalWrite(grnPin, LOW);
      delayMicroseconds(off);
    }
  } 
}



void yellowtogreen()
{
   digitalWrite(grnPin, HIGH);
   digitalWrite(bluPin, LOW);

  // fade down red
  for(byte i=1; i<100; i++) {
    byte on  = 100-i;
    byte off = i;
    for( byte a=0; a<100; a++ ) {
      digitalWrite(redPin, HIGH);
      delayMicroseconds(on);
      digitalWrite(redPin, LOW);
      delayMicroseconds(off);
    }
  } 
}


void greentocyan()
{
   digitalWrite(grnPin, HIGH);
   digitalWrite(redPin, LOW);

  // fade up blue
  for(byte i=1; i<100; i++) {
    byte on  = i;
    byte off = 100-on;
    for( byte a=0; a<100; a++ ) {
      digitalWrite(bluPin, HIGH);
      delayMicroseconds(on);
      digitalWrite(bluPin, LOW);
      delayMicroseconds(off);
    }
  } 
}



void cyantoblue()
{
   digitalWrite(bluPin, HIGH);
   digitalWrite(redPin, LOW);

  // fade down green
  for(byte i=1; i<100; i++) {
    byte on  = 100-i;
    byte off = i;
    for( byte a=0; a<100; a++ ) {
      digitalWrite(grnPin, HIGH);
      delayMicroseconds(on);
      digitalWrite(grnPin, LOW);
      delayMicroseconds(off);
    }
  } 
}


void bluetomajenta()
{
   digitalWrite(bluPin, HIGH);
   digitalWrite(grnPin, LOW);

  // fade up red
  for(byte i=1; i<100; i++) {
    byte on  = i;
    byte off = 100-on;
    for( byte a=0; a<100; a++ ) {
      digitalWrite(redPin, HIGH);
      delayMicroseconds(on);
      digitalWrite(redPin, LOW);
      delayMicroseconds(off);
    }
  } 
}



void majenatored()
{
   digitalWrite(redPin, HIGH);
   digitalWrite(grnPin, LOW);

  // fade down blue
  for(byte i=1; i<100; i++) {
    byte on  = 100-i;
    byte off = i;
    for( byte a=0; a<100; a++ ) {
      digitalWrite(bluPin, HIGH);
      delayMicroseconds(on);
      digitalWrite(bluPin, LOW);
      delayMicroseconds(off);
    }
  } 
}

but i want it to fade through the colors faster. How can i do thi in the code?

Diddle around for less time between steps. I'm sure that you can see what causes the Arduino to do nothing for a while. If not, here's a hint. It starts with delay.