attiny85 software pwm

Using Arduino LEDs and Multiplexing
6

Any joy with that code?
I've been trying to "shinkify" my project onto an ATtiny85 and for some reason only one pin seems to be working and maybe I need more usable pins

It's just the Fire effect LED project from Michael McRoberts' book Beginning Arduino. I think I'm attempting to run before I can walk. I've changed the pin numbers in the code (not in the below example) for loading onto the Tiny but only one pin lights but it does flicker nicely.

// LED Fire Effect
int ledPin1 = 9;
int ledPin2 = 10;
int ledPin3 = 11;

void setup()
{
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
}

void loop()
{
  analogWrite(ledPin1, random(120)+135);
  analogWrite(ledPin2, random(120)+135);
  analogWrite(ledPin3, random(120)+135);
  delay(random(100));
}

I hope someone can point me in the right direction. I'm such a noob at this and I appear to be going in circles with my searches.