How to create Arduino LED 3d printed Christmas Tree Lamp

#include <FastLED.h>
#define LED_PIN     5
#define NUM_LEDS    10
#define BRIGHTNESS  64
#define LED_TYPE    WS2811
#define COLOR_ORDER GRB

int OldState [NUM_LEDS];
int NewState [NUM_LEDS];
int Color = 145;
int ColorChange=0;
unsigned long timer=0;


CRGB leds[NUM_LEDS];
void setup() {
    delay( 3000 ); // power-up safety delay
    FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
    FastLED.setBrightness(  BRIGHTNESS );
    for( int i = 0; i < NUM_LEDS-1; ++i) if(Color+random(30)>255) OldState[i] = Color+random(30);else OldState[i] = Color+random(30)-255;
}

void loop() {
  if (millis()-timer>10000){
    timer = millis();
    Color=Color+20;
    if (Color>255)Color=Color-255;
  }

  for( int i = 0; i < NUM_LEDS-1; ++i)  if(Color+random(30)>255) NewState[i] = Color+random(30);else NewState[i] = Color+random(30)-255;
  for (int j=0;j<30;j++){
    for( int i = 0; i < NUM_LEDS-1; ++i) {
      if (OldState[i]<NewState[i])ColorChange=1; 
      if (OldState[i]>NewState[i])ColorChange=-1;
      OldState[i]=OldState[i]+ColorChange;
      if (OldState[i]>255)OldState[i]=OldState[i]-255;
      leds[i] = CHSV(OldState[i], 255, 255);
      ColorChange=0;
  }
    FastLED.show();
  delay(40);
  }
  for( int i = 0; i < NUM_LEDS-1; ++i) {
       OldState[i] = NewState[i];
  }
  leds[9] = CHSV(Color+100, 255, 255);
}