Add Jack-o'-Lantern code

Circuit_Playground_Jack_o_Lantern/JackOLantern_CircuitPlayground.ino

@@ -0,0 +1,30 @@
+// Jack-o-Lantern sketch for Adafruit Circuit Playground (Classic or Express)
+
+#include "Adafruit_CircuitPlayground.h"
+
+void setup() {
+  CircuitPlayground.begin();
+  CircuitPlayground.setBrightness(255); // LEDs full blast!
+}
+
+uint8_t prev = 128;              // Start brightness in middle
+
+void loop() {
+  uint8_t lvl = random(64, 192); // End brightness at 128±64
+  split(prev, lvl, 32);          // Start subdividing, ±32 at midpoint
+  prev = lvl;                    // Assign end brightness to next start
+}
+
+void split(uint8_t y1, uint8_t y2, uint8_t offset) {
+  if(offset) { // Split further into sub-segments w/midpoint at ±offset
+    uint8_t mid = (y1 + y2 + 1) / 2 + random(-offset, offset);
+    split(y1 , mid, offset / 2); // First segment (offset is halved)
+    split(mid, y2 , offset / 2); // Second segment (ditto)
+  } else { // No further subdivision - y1 determines LED brightness
+    uint32_t c = (((int)(pow((float)y1 / 255.0, 2.7) * 255.0 + 0.5) // Gamma
+                 * 0x1004004) >> 8) & 0xFF3F03; // Expand to 32-bit RGB color
+    for(uint8_t i=0; i<10; i++) CircuitPlayground.strip.setPixelColor(i, c);
+    CircuitPlayground.strip.show();
+    delay(4);
+  }
+}

Circuit_Playground_Jack_o_Lantern/JackOLantern_HalloWing.ino

@@ -0,0 +1,33 @@
+// Jack-o-Lantern sketch for Adafruit Hallowing
+
+#include "Adafruit_NeoPixel.h"
+
+#define NUM_PIXELS 30
+
+Adafruit_NeoPixel strip(NUM_PIXELS, 4, NEO_GRB + NEO_KHZ800);
+
+void setup() {
+  strip.begin();
+}
+
+uint8_t prev = 128;              // Start brightness in middle
+
+void loop() {
+  uint8_t lvl = random(64, 192); // End brightness at 128±64
+  split(prev, lvl, 32);          // Start subdividing, ±32 at midpoint
+  prev = lvl;                    // Assign end brightness to next start
+}
+
+void split(uint8_t y1, uint8_t y2, uint8_t offset) {
+  if(offset) { // Split further into sub-segments w/midpoint at ±offset
+    uint8_t mid = (y1 + y2 + 1) / 2 + random(-offset, offset);
+    split(y1 , mid, offset / 2); // First segment (offset is halved)
+    split(mid, y2 , offset / 2); // Second segment (ditto)
+  } else { // No further subdivision - y1 determines LED brightness
+    uint32_t c = (((int)(pow((float)y1 / 255.0, 2.7) * 255.0 + 0.5) // Gamma
+                 * 0x1004004) >> 8) & 0xFF3F03; // Expand to 32-bit RGB color
+    for(uint8_t i=0; i<NUM_PIXELS; i++) strip.setPixelColor(i, c);
+    strip.show();
+    delay(4);
+  }
+}

Circuit_Playground_Jack_o_Lantern/jack_o_lantern_circuit_playground.py

@@ -0,0 +1,37 @@
+"""Jack-o'-Lantern flame example Adafruit Circuit Playground Express"""
+
+import math
+import board
+import neopixel
+try:
+    import urandom as random  # for v1.0 API support
+except ImportError:
+    import random
+
+NUMPIX = 10        # Number of NeoPixels
+PIXPIN = board.D8  # Pin where NeoPixels are connected
+STRIP = neopixel.NeoPixel(PIXPIN, NUMPIX, brightness=1.0)
+PREV = 128
+
+def split(first, second, offset):
+    """
+    Subdivide a brightness range, introducing a random offset in middle,
+    then call recursively with smaller offsets along the way.
+    @param1 first:  Initial brightness value.
+    @param1 second: Ending brightness value.
+    @param1 offset: Midpoint offset range is +/- this amount max.
+    """
+    if offset != 0:
+        mid = ((first + second + 1) / 2 + random.randint(-offset, offset))
+        offset = int(offset / 2)
+        split(first, mid, offset)
+        split(mid, second, offset)
+    else:
+        level = math.pow(first / 255.0, 2.7) * 255.0 + 0.5
+        STRIP.fill((int(level), int(level / 8), int(level / 48)))
+        STRIP.write()
+
+while True:  # Loop forever...
+    LVL = random.randint(64, 191)
+    split(PREV, LVL, 32)
+    PREV = LVL

Circuit_Playground_Jack_o_Lantern/jack_o_lantern_hallowing.py

@@ -0,0 +1,37 @@
+"""Jack-o'-Lantern flame example Adafruit Hallowing"""
+
+import math
+import board
+import neopixel
+try:
+    import urandom as random  # for v1.0 API support
+except ImportError:
+    import random
+
+NUMPIX = 30                       # Number of NeoPixels
+PIXPIN = board.EXTERNAL_NEOPIXEL  # Pin where NeoPixels are connected
+STRIP = neopixel.NeoPixel(PIXPIN, NUMPIX, brightness=1.0)
+PREV = 128
+
+def split(first, second, offset):
+    """
+    Subdivide a brightness range, introducing a random offset in middle,
+    then call recursively with smaller offsets along the way.
+    @param1 first:  Initial brightness value.
+    @param1 second: Ending brightness value.
+    @param1 offset: Midpoint offset range is +/- this amount max.
+    """
+    if offset != 0:
+        mid = ((first + second + 1) / 2 + random.randint(-offset, offset))
+        offset = int(offset / 2)
+        split(first, mid, offset)
+        split(mid, second, offset)
+    else:
+        level = math.pow(first / 255.0, 2.7) * 255.0 + 0.5
+        STRIP.fill((int(level), int(level / 8), int(level / 48)))
+        STRIP.write()
+
+while True:  # Loop forever...
+    LVL = random.randint(64, 191)
+    split(PREV, LVL, 32)
+    PREV = LVL