xymap.cpp

#include <FastLED.h>

struct PT { uint8_t x, y;};
#define NUM_LEDS 20

CRGB leds[NUM_LEDS];
PT xy[] = { {5,0}, {6,1}, {7,2}, {8,3}, {9,4}, {10,5}, {9,6}, {8,7}, {7,8}, {6,9}, {5,10}, {4,9}, {3,8}, {2,7}, {1,6}, {0,5}, {1,4}, {2,3}, {3,2}, {4,1} };

void setup() {
  // ... 
}

void loop() {
  static uint8_t hue=0;
  for(int i = 0; i < NUM_LEDS; i++) {
    leds[i] = CHSV(hue, 192, inoise8_raw(xy[i].x << 8, xy[i].y << 8, millis()));
  }
  hue++;
  FastLED.delay(1000/30);
}