From 2425b703505a00f6193665bfc021370947588049 Mon Sep 17 00:00:00 2001
From: Alan Wang <44191076+alankrantas@users.noreply.github.com>
Date: Sun, 14 Jun 2020 15:53:35 +0800
Subject: [PATCH] Update README.md

---
 README.md | 44 ++++++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/README.md b/README.md
index bc1bebe..17e700a 100644
--- a/README.md
+++ b/README.md
@@ -43,19 +43,25 @@ dir(microbit)
 
 ## Some Lesser Known Facts
 
-Since both Python and MicroPython are interpreted languages, they eat a lot of memory. Also, the hex file generated by micro:bit Python editors are consisted of 2 parts: the MicroPython firmware (up to 248 KB) and user's script (up to only 8 KB). See [Firmware Hex File](https://microbit-micropython.readthedocs.io/en/latest/devguide/hexformat.html). Which means it's less likely to build bigger projects with micro:bit's MicroPython.
+Since MicroPython, like standard Python, is a interpreted language, it eats a lot of memory. A slightly bigger program may cause MemoryError (out of memory). Also due to this reason, there is no room for the Bluetooth driver.
+
+Another limit is that the MicroPython hex file are consisted of 2 parts: the MicroPython firmware (up to 248 KB) and user's script (up to only 8 KB). See [Firmware Hex File](https://microbit-micropython.readthedocs.io/en/latest/devguide/hexformat.html). Which means it's less likely to build bigger projects with micro:bit's MicroPython.
 
 One way to "minimize" your script size is to use 1-space indents instead of 4.
 
-micro:bit's MicroPython is based on Python 3.4. Which means many built-in Python advanced feaetures, like string.format(), list comprehension, list slice, variable unpacking, lambda function, decorators, generators, @classmethod, @staticmethod, etc. can be used as well.
+micro:bit's MicroPython is based on Python 3.4. Which means many built-in Python advanced feaetures are supported. Although some features are dropped as well to save memory.
 
-Also, about how micro:bit get its own version of MicroPython: [The Story of MicroPython on the BBC micro:bit](http://ntoll.org/article/story-micropython-on-microbit) by Nicholas H. Tollervey, who also created the [Mu editor](https://codewith.mu/).
+Nicholas H. Tollervey - also the creator of [Mu editor](https://codewith.mu/) - has an interesting account about [How BBC micro:bit get its MicroPython](http://ntoll.org/article/story-micropython-on-microbit).
 
-## Recursion is Not Welcomed
+## Editor of Choice
 
-Since micro:bit has very limited memory, the recursion depth is severely limited. Only [8 nested function calls or so](https://mail.python.org/pipermail/microbit/2016-February/000896.html) can be used without triggering RuntimeError. 
+The official [Python online editor](https://python.microbit.org/v/2.0) does not need installation and can be used anywhere with Internet and Chrome web browser. Support Web-USB. It's ok to use, really.
 
-## Why You Shouldn't Use * For Import
+Personally, I would perfer [Mu editor](https://codewith.mu/) for any beginners. It has code check, (limited) auto-complete and can automatically detect/upload code to your micro:bit.
+
+If you have experiences in standard Python or MicroPython with ESP8266/ESP32 (or CircuitPython), you can consider [Thonny](https://thonny.org/) which allows you to access micro:bit's REPL directly without having to switch tabs.
+
+## Why You Shouldn Aviud Import *
 
 The following import statement
 
@@ -63,9 +69,9 @@ The following import statement
 from microbit import *
 ```
 
-is a bad idea. This imports everything of the microbit module even you don't need many of the features and wastes extra memory.
+is a bad idea. This imports everything from the big microbit module even you don't need many of the features and thus waste memory.
 
-Instead, you should only import sub-modules you are going to use:
+Instead, you should import the only submodules you are going to use:
 
 ```python
 from microbit import pin0, display, sleep
@@ -88,13 +94,9 @@ gc.enable() # auto memory recycle
 gc.collect() # force memory recycle
 ```
 
-## Editor of Choice
+## Recursion is Not Welcomed
 
-The official [Python online editor](https://python.microbit.org/v/2.0) does not need installation and can be used anywhere with Internet and Chrome web browser. Support Web-USB. It's ok to use, really.
-
-Personally, I would perfer [Mu editor](https://codewith.mu/) for any beginners. It has code check, (limited) auto-complete and can automatically detect/upload code to your micro:bit.
-
-If you have experiences with MicroPython with ESP8266/ESP32 or CircuitPython, you can consider [Thonny](https://thonny.org/) which allows you to access micro:bit's REPL directly without having to upload hex file.
+Recursion depth (how many level can a function calls itself) is severely limited because of the memory constraint. Only [8 nested function calls or so](https://mail.python.org/pipermail/microbit/2016-February/000896.html) can be used without triggering RuntimeError. So sadly it's not possible to do some popular algorithms on micro:bit.
 
 ## Classic Blinky
 
@@ -150,7 +152,7 @@ while True:
     for _ in range(2):
         fillScreen()
         sleep(100)
-        fillScreen(0)
+        display.clear()
         sleep(100)
     
     for i in range(9):
@@ -214,7 +216,7 @@ while True:
         since2 = utime.ticks_ms()
 ```
 
-## A More Convenient Pin Class
+## A More Convenient Pin Class?
 
 Make a Pin class to "rename" existing pin methods.
 
@@ -254,7 +256,7 @@ while True:
     sleep(50)
 ```
 
-## Another Version of Pin Class
+## Simpler Alternate Pin Class
 
 Use **namedtuple** as a simple Pin class. Might save more memory than regular class.
 
@@ -432,6 +434,8 @@ while True:
 
 ## Calcualte Fibonacci Sequence
 
+[Fibonacci sequence](https://en.wikipedia.org/wiki/Fibonacci_number)
+
 ```python
 from microbit import display
 
@@ -448,7 +452,7 @@ display.scroll(b)
 
 ## Calcuate a List of Prime Numbers
 
-Prime numbers (except 2, 3) are either 6n - 1 or 6n + 1.
+Prime numbers (except 2, 3) are either 6n - 1 or 6n + 1. So we check if a number of 6n - 1/6n + 1 can be divided with any existing primes in the list. If not, it is a prime number and can be added to the list.
 
 ```python
 from microbit import display
@@ -473,7 +477,7 @@ for prime in primes:
 
 ## Conway's Game of Life on 5x5 LED Display
 
-The code would reset the micro:bit if there's no cell left or the cells are stable.
+The code would reset the micro:bit if there's no cell left or the cells are stable. Although sometimes it may be locked into a state with the same alternating cell numbers and need manual reset.
 
 ```python
 from microbit import display
@@ -548,7 +552,7 @@ while True:
 
 This allows you to enter your message and display it as Morse code on the LED screen. Go to the REPL mode and reset micro:bit to make it work.
 
-If you attach a passive buzzer between pin 0 and ground you can hear it too.
+If you attach a passive buzzer between pin 0 and ground you can hear the Morse code too.
 
 ```python
 from microbit import display, Image, sleep