examples: Add falling blocks game.

Created at PyCon2016, I donate this to public domain!

examples/fallingblocks.py

@@ -0,0 +1,79 @@
+from microbit import *
+import random
+
+
+class FallingBlocks:
+    def __init__(self):
+        self.screen = Image(5, 5)
+        self.movingDot = None
+        self.points = 0
+        self.gameOver = False
+
+    def addDot(self, i):
+        if self.screen.get_pixel(i, 0) == 9:
+            self.gameOver = True
+        else:
+            self.movingDot = (i, 0)
+            self.screen.set_pixel(i, 0, 9)
+
+    def stepDown(self):
+        x, y = self.movingDot
+        if y + 1 < 5 and self.screen.get_pixel(x, y + 1) == 0:
+            self.screen.set_pixel(x, y, 0)
+            self.screen.set_pixel(x, y + 1, 9)
+            self.movingDot = (x, y + 1)
+        else:
+            self.movingDot = None
+
+    def move(self, v):
+        x, y = self.movingDot
+        if x + v >= 0 and x + v < 5 and self.screen.get_pixel(x + v, y) == 0:
+            self.screen.set_pixel(x, y, 0)
+            self.screen.set_pixel(x + v, y, 9)
+            self.movingDot = (x + v, y)
+
+    def hasMovingDot(self):
+        return self.movingDot != None
+
+    def screenDown(self):
+        self.screen = self.screen.shift_down(1)
+
+    def checkLine(self):
+        if all(self.screen.get_pixel(i, 4) == 9 for i in range(5)):
+            self.points += 1
+            self.screenDown()
+            return True
+        return False
+
+
+while True:
+    SPEED = 500
+    SPEED2 = 200
+    STEP = 10
+    game = FallingBlocks()
+    while not game.gameOver:
+        if not game.hasMovingDot():
+            game.addDot(random.randint(0, 4))
+        display.show(game.screen)
+        if not game.gameOver:
+            t0 = running_time()
+            while running_time() - t0 < SPEED:
+                reading = accelerometer.get_x()
+                if reading > 20:
+                    game.move(1)
+                elif reading < -20:
+                    game.move(-1)
+                display.show(game.screen)
+                sleep(SPEED2)
+            game.stepDown()
+            if game.checkLine():
+                if SPEED >= STEP:
+                    SPEED -= STEP
+                if SPEED2 >= STEP:
+                    SPEED2 -= STEP
+
+    while True:
+        display.scroll("Game Over !")
+        display.scroll(str(game.points) + " points")
+        if button_a.was_pressed():
+            break