Add a 20-sided die roller to the examples

examples/d20.py

@@ -0,0 +1,35 @@
+"""
+    d20.py
+    ~~~~~~~~
+    Rolls a 20-sided die. If a 20 is rolled, display a short series of images and
+    play some music. The skull image represents 20. If a 1 is rolled, display a sad
+    face and play some music.
+    The music isn't required, but if you want to hear it, you'll need a
+    speaker/buzzer/headphones connected to P0 and GND.
+"""
+
+from microbit import *
+import random
+import music
+
+# A list of images to display if 20 (crit) is rolled
+critimages = [Image.HEART, Image.HEART_SMALL, Image.SKULL]
+
+# Loop forever
+while True:
+    # User can press button A or shake the microbit to "roll"
+    if button_a.was_pressed() or accelerometer.was_gesture("shake"):
+        dice = random.randint(1, 20)
+        if dice == 20:
+            # Set wait to False to that it's not blocking.
+            # Music will play while images are cycled through.
+            music.play(music.POWER_UP, wait=False)
+            display.show(critimages, delay=1400)
+        elif dice == 1:
+            music.play(music.WAWAWAWAA, wait=False)
+            display.show(Image.SAD)
+        # For single digit numbers, show the number. Scroll for double-digits.
+        elif 10 > dice > 1:
+            display.show(str(dice))
+        else:
+            display.scroll(str(dice), wait=False, loop=True)