selecting multiple ws2812 leds to turn off in a string

Hello There,

i am busy with a project where i am using a string of 50pcs ws2812s leds. I want to have a 'theatre Chase sample' I got that part working very nice...Now i have to implement a button action that when the button is pressed the next 'scene' wil start. The next scene will be like 10 leds will turn off in the middle of the string. The rest of the leds will keep their program of 'theatr Chase sample'.
I have this already...

#include <Adafruit_NeoPixel.h>

#define PIN 6
#define BRIGHTNESS 90        // Max. brightness in %


// Parameter 1 = number of pixels in strip
// Parameter 2 = pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
//   NEO_KHZ800  800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
//   NEO_KHZ400  400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
//   NEO_GRB     Pixels are wired for GRB bitstream (most NeoPixel products)
//   NEO_RGB     Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
Adafruit_NeoPixel strip = Adafruit_NeoPixel(60, PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  strip.begin();
  strip.setBrightness( (255 / 100) * BRIGHTNESS );
  strip.show(); // Initialize all pixels to 'off'
}

void loop() {
  
  // Send a theater pixel chase in...
  theaterChase(strip.Color(127,   0,   0), 50); // Red
}



//Theatre-style crawling lights.
void theaterChase(uint32_t c, uint8_t wait) {
  for (int j=0; j<10; j++) {  //do 10 cycles of chasing
    for (int q=0; q < 3; q++) {
      for (int i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, c);    //turn every third pixel on
        strip.setPixelColor(10, 0,   255,   0);  // set LED 10 in the selected RGB code color
      }
      strip.show();

      delay(wait);

      for (int i=0; i < strip.numPixels(); i=i+3) {
        strip.setPixelColor(i+q, 0);        //turn every third pixel off
      }
    }
  }
}

And this part of the code sets Led number 10 to green. But now i want multiple leds..like led 10 till led 20 to go green.
strip.setPixelColor(10, 0, 255, 0); // set LED 10 in the selected RGB code color

When this is done, i want to implement the button section....but more questions i have will come when i am starting with that part.

hope someone can help me..

thanks

I figured this problem out myself now....

I am now busy with using 2 digital WS2812 strips on 2 different ports on the arduino. The problem is that i have 2 'theatrechase' programs that i want to run on both ledstrips. My problem now is that when i show both programs ledstrip 1 runs the program, so i se the 'theatrechase' prgram running, but when the second strip starts it program, the first strip stops the program..i just see the 'theatherchase' programm in a halt....then it switches the theathercase program from strip 2 to strip 1 as when strips 1 runs, strip 2 freezes, when strip 2 runs, strip 1 freezes....

what can be the problem???