2.1.28, initiation update to PXT v5.28.24 (#54)

docs/projects/flashing-heart.md

@@ -0,0 +1,46 @@
+# Flashing Heart
+
+## Introduction @unplugged
+
+Learn how to use the LEDs and make a flashing heart! 
+(Want to learn how lights work? [Watch this video](https://youtu.be/qqBmvHD5bCw)).
+
+
+![Heart shape in the LEDs](/docs/calliope/tutorials/01_flashing_heart_animation.gif)
+
+## Step 1 @fullscreen
+
+Place the ``||basic:show leds||`` block in the ``||basic:forever||`` block and draw a heart.
+
+![An animation that shows how to drag a block and paint a heart](/docs/calliope/tutorials/add_show_led.gif)
+
+## Step 2 @fullscreen
+
+Place another ``||basic:show leds||`` block. You can leave it blank and draw what you want.
+
+```blocks
+basic.forever(function() {
+    basic.showLeds(`
+        . # . # .
+        # # # # #
+        # # # # #
+        . # # # .
+        . . # . .`);
+    basic.showLeds(`
+        . . . . .
+        . . . . .
+        . . . . .
+        . . . . .
+        . . . . .`);
+})
+```
+
+## Step 3 @fullscreen
+
+Look at the virtual @boardname@, you should see the heart and your drawing blink on the screen.
+
+![Heart shape in the LEDs](/docs/calliope/tutorials/01_flashing_heart_animation.gif)
+
+## Step 4 @fullscreen
+
+If you have a @boardname@ connected, click ``|Download|`` to transfer your code and watch the hearts flash!