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Central Access Point

The Central Access Point is running on a Raspberry Pi Zero W

Network configuration

Install necessary SWs

    $ sudo apt update
    $ sudo apt full-upgrade
    # dnsmasq - This program has extensive features, but for our purposes we are using it as a DHCP server for our WiFi AP.
    # hostapd - This program defines our AP’s physical operation based on driver configuration. 

    $ sudo apt-get install dnsmasq hostapd

Install grafana Ubuntu and Debian(ARMv6): https://grafana.com/grafana/download/9.3.6?edition=enterprise&platform=arm

    sudo apt-get install -y adduser libfontconfig1 musl
    wget https://dl.grafana.com/enterprise/release/grafana-enterprise-rpi_9.3.6_armhf.deb
    sudo dpkg -i grafana-enterprise-rpi_9.3.6_armhf.deb

Config file: /etc/grafana/grafana.ini

Install sqlite plugin

    grafana-cli plugins install frser-sqlite-datasource

Enable and Start grafana

    sudo /bin/systemctl enable grafana-server
    sudo /bin/systemctl start grafana-server

Configurations

  • Check the existing network
    This is what you can see before configuring

    pi@raspberrypi:~$ iw dev
phy#0
    Unnamed/non-netdev interface
            wdev 0x4
            addr ba:27:eb:07:28:1f
            type P2P-device
            txpower 31.00 dBm
    Interface wlan0
            ifindex 2
            wdev 0x1
            addr b8:27:eb:ff:ff:ff
            ssid <YOUR HOME SSID> 
            type managed
            channel 1 (2437 MHz), width: 20 MHz, center1: 2437 MHz
            txpower 31.00 dBm

  • Configure dnsmasq
    Let’s call our new interface for AP to uap0 Here we can define the IP interval what we use for the nodes connecting to this AP. In this case it will be between 192.168.50.50 and 192.168.50.150

    pi@raspberrypi:~$ /etc/dnsmasq.conf
  interface=lo,uap0
  no-dhcp-interface=lo,wlan0
  bind-interfaces
  server=8.8.8.8
  domain-needed
  bogus-priv
  dhcp-range=192.168.50.50,192.168.50.150,24h

  • Configure hostapd
    Here the channel is hardcoded. There is a dynamic and better way to find out the right channel. I’ll show it later

    pi@raspberrypi:~$ vi /etc/hostapd/hostapd.conf
  interface=uap0
  ssid=Central-Station-006 
  hw_mode=g 
  channel=1 
  macaddr_acl=0 
  auth_algs=1 
  ignore_broadcast_ssid=0 
  wpa=2 
  wpa_passphrase=viragfal 
  wpa_key_mgmt=WPA-PSK 
  wpa_pairwise=TKIP 
  rsn_pairwise=CCMP

  • Configure wifi network interface file

     pi@raspberrypi:~$ vi /etc/wpa_supplicant/wpa_supplicant.conf

   ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev 
   update_config=1 

   network={ 
       ssid="****" 
       psk="****" 
       key_mgmt=WPA-PSK 
       id_str="AP1" 
   } 

   network={ 
       ssid="****" 
       psk="****" 
       key_mgmt=WPA-PSK 
       id_str="AP2" 
   }

  • Configure AP interface file

     pi@raspberrypi:~$ vi /etc/network/interfaces
   source-directory /etc/network/interfaces.d 

   auto lo 
   auto uap0 
   auto wlan0 

   iface lo inet loopback 

   allow-hotplug uap0 
   iface uap0 inet static 
       address 192.168.50.3 
       netmask 255.255.255.0 
       hostapd /etc/hostapd/hostapd.conf 

   allow-hotplug wlan0 
   iface wlan0 inet manual 
       wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf 

   iface AP1 inet dhcp 
   iface AP2 inet dhcp

  • Script to put all together

     pi@raspberrypi:~$ /usr/local/bin/hostapdstart.sh
   #!/bin/bash 

   mac=`sudo ifconfig |grep ether | sed 's/ether \([a-f0-9][a-f0-9]:[a-f0-9][a-f0-9]:[a-f0-9][a-f0-9]:[a-f0-9][a-f0-9]:[a-f0-9][a-f0-9]:[a-f0-9][a-f0-9]\).*/\1/g' | head -n 1` 

   sudo /sbin/iw phy phy0 interface add uap0 type __ap 
   sudo /bin/ip link set uap0 address $mac 

   sudo ifdown --force wlan0 
   sudo ifdown --force uap0 

   sudo ifup uap0 
   sudo ifup wlan0 

   # Fetch wifi channel 
   CHANNEL=`iwlist wlan0 channel | grep Current | sed 's/.*Channel \([0-9]*\).*/\1/g'` 
   export CHANNEL 

   # Create the config for hostapd 
   #cat /etc/hostapd/hostapd.conf.tmpl | envsubst > /etc/hostapd/hostapd.conf 

   # Uncomment the two following lines to get access to internet 
   #sysctl net.ipv4.ip_forward=1 
   #iptables -t nat -A POSTROUTING -s 192.168.50.0/24 ! -d 192.168.50.0/24 -j MASQUERADE 

   sudo systemctl restart hostapd 
   sleep 10 
   sudo systemctl restart dnsmasq 
   sleep 10 
   sudo systemctl restart dhcpcd

  • unmask hostapd

       pi@raspberrypi:~$ sudo systemctl unmask hostapd
   pi@raspberrypi:~$ sudo systemctl enable hostapd
   pi@raspberrypi:~$ sudo systemctl start hostapd

  • Run the script just after the reboot automatically
    In the crontab file:

    root@raspberrypi:~$ crontab -e
   @reboot /usr/local/bin/hostapdstart.sh

  • Check the existing network after the configuration
    You can see the new Interface: uap0

    root@raspberrypi:~# iw dev
   phy#0 
       Unnamed/non-netdev interface 
	       wdev 0x3 
	       addr ba:27:eb:97:d5:fe 
	       type P2P-device 
	       txpower 31.00 dBm 
       Interface uap0 
	       ifindex 3 
	       wdev 0x2 
	       addr b8:27:eb:97:d5:fe 
	       ssid Central-Station-006 
	       type AP 
	       channel 1 (2412 MHz), width: 20 MHz, center1: 2412 MHz 
	       txpower 31.00 dBm 
	       
           Interface wlan0
               ifindex 2
                   wdev 0x1
                   addr b8:27:eb:ff:ff:ff
                   ssid <YOUR HOME SSID> 
                   type managed
                   channel 1 (2437 MHz), width: 20 MHz, center1: 2437 MHz
                   txpower 31.00 dBm		      
    root@raspberrypi:~# ip addr 
   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 
       link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 
       inet 127.0.0.1/8 scope host lo 
	       valid_lft forever preferred_lft forever 
       inet6 ::1/128 scope host
	       valid_lft forever preferred_lft forever 
   2: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 
       link/ether b8:27:eb:97:d5:fe brd ff:ff:ff:ff:ff:ff 
       inet 192.168.0.103/24 brd 192.168.0.255 scope global dynamic wlan0 
	       valid_lft 1966sec preferred_lft 1966sec 
       inet6 fdaa:bbcc:ddee:0:ba27:ebff:fe97:d5fe/64 scope global dynamic mngtmpaddr
	       valid_lft 2006054648sec preferred_lft 2006054648sec 
       inet6 fe80::ba27:ebff:fe97:d5fe/64 scope link
	       valid_lft forever preferred_lft forever 
   3: uap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 
       link/ether b8:27:eb:97:d5:fe brd ff:ff:ff:ff:ff:ff 
       inet 192.168.50.3/24 brd 192.168.50.255 scope global uap0 
	       valid_lft forever preferred_lft forever 
       inet6 fe80::ba27:ebff:fe97:d5fe/64 scope link
	       valid_lft forever preferred_lft forever

Configuration hierarchy

graph LR
/var/spool/cron/crontabs/root --> /home/pi/Projects/diy-greenwall/Software/Central.AccessPoint-RaspberryPi/python/start
/var/spool/cron/crontabs/root --> /usr/local/bin/hostapdstart.sh

/usr/local/bin/hostapdstart.sh --> /etc/dnsmasq.conf
/usr/local/bin/hostapdstart.sh --> /etc/network/interfaces

/etc/network/interfaces --> /etc/hostapd/hostapd.conf
/etc/network/interfaces --> /etc/wpa_supplicant/wpa_supplicant.conf
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Controller software

Create virtual environment for Python

pi@raspberrypi:~ $ sudo apt install python3-venv
pi@raspberrypi:~ $ cd /var/www/greenwall/python
pi@raspberrypi:/var/www/greenwall/python $ python3 -m venv env

Install prerequisites

pi@raspberrypi:~ $ sudo apt-get install iptables-persistent

pi@raspberrypi:~ $ sudo apt-get install libapache2-mod-wsgi-py3

pi@raspberrypi:/var/www/greenwall/python $ source env/bin/activate
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip install requests
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip3 install python-dateutil 
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ python -m pip install flask
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip install Flask-Classful==0.15.0b1
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip3 install -U flask-cors
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip3 install rpi_lcd
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip3 install evdev
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip3 install psutil
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip install scipy --no-cache-dir
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip install matplotlib
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip3 install pandas
(env) pi@raspberrypi:/var/www/greenwall/python/env/bin $ pip3 install natsort






$ sudo apt-get install python3-sklearn python3-sklearn-lib  
$ pip3 install opencv-python

Clone the diy-greenwall project

First you should clone the diy-greenwall project from the GitHub.

 $ cd
 $ mkdir Projects
 $ git clone https://github.com/dallaszkorben/diy-greenwall.git

As you need only the hierarcy under the diy-greenwall/Software/Central.AccessPoint-RaspberryPi folder, on the Rasberry Pi, you can filter out the not necesary parts. But it is not mandatory to do

  $ cd diy-greenwall
  $ git  filter-branch -f --subdirectory-filter Software/Central.AccessPoint-RaspberryPi

Under the python folder, you can see the following hierarchy of the python code:

.
├── config
│   ├── config.py
│   ├── ini_location.py
│   ├── __init.py__
│   ├── permanent_data.py
│   ├── property.py
│   └── __pycache__
│       ├── config.cpython-37.pyc
│       ├── ini_location.cpython-37.pyc
│       ├── permanent_data.cpython-37.pyc
│       └── property.cpython-37.pyc
├── controlbox
│   ├── controlbox.py
│   ├── __init__.py
│   └── __pycache__
│       ├── controlbox.cpython-37.pyc
│       └── __init__.cpython-37.pyc
├── exceptions
│   ├── __init.py__
│   ├── invalid_api_usage.py
│   └── __pycache__
│       └── invalid_api_usage.cpython-37.pyc
├── graph
│   ├── graph_level.py
│   ├── __init.py__
│   └── __pycache__
│       └── graph_level.cpython-37.pyc
├── greenwall.wsgi
├── ky040
│   ├── __init__.py
│   ├── ky040.py
│   └── __pycache__
│       ├── __init__.cpython-37.pyc
│       ├── ky040.cpython-37.pyc
│       └── KY040.cpython-37.pyc
├── restserver
│   ├── endpoints
│   │   ├── ep_info_functions.py
│   │   ├── ep_info_graph.py
│   │   ├── ep_info_timestamp.py
│   │   ├── ep_level_add.py
│   │   ├── ep.py
│   │   ├── __init.py__
│   │   ├── __pycache__
│   │   │   ├── ep.cpython-37.pyc
│   │   │   ├── ep_info_functions.cpython-37.pyc
│   │   │   ├── ep_info_graph.cpython-37.pyc
│   │   │   ├── ep_info_level.cpython-37.pyc
│   │   │   ├── ep_info_timestamp.cpython-37.pyc
│   │   │   ├── ep_info_trend.cpython-37.pyc
│   │   │   ├── ep_level_add.cpython-37.pyc
│   │   │   └── ep_level_read.cpython-37.pyc
│   │   ├── representations.py
│   │   └── ~toDelete
│   │       └── ep_info_level.py
│   ├── gradual_thread_controller.py
│   ├── __init.py__
│   ├── __pycache__
│   │   ├── gradual_thread_controller.cpython-37.pyc
│   │   ├── representations.cpython-37.pyc
│   │   ├── view_info.cpython-37.pyc
│   │   ├── view_level.cpython-37.pyc
│   │   └── ws_greenwall.cpython-37.pyc
│   ├── representations.py
│   ├── view_info.py
│   ├── view_level.py
│   └── ws_greenwall.py
├── start.py
└── utilities
    ├── __init.py__
    ├── __pycache__
    │   └── report.cpython-37.pyc
    └── report.py

Install Web server on Raspberry Pi

Apache2 server should be installed and configured to allow browsers to connect and see the statuses of Sensors

  • Find the codes under web-location/greenwall/ folder

    .
└── greenwall
    ├── favicon.ico
    ├── /graph-images
    ├── /index.html
    └── /script
        ├── /jquery
        │   └── jquery-3.6.0.min.js
        └── /jquery-ui
            ├── AUTHORS.txt
            ├── /external
            │   └── /jquery
            │       └── jquery.js
            ├── images              
            ├── index.html
            ├── jquery-ui.css
            ├── jquery-ui.js
            ├── jquery-ui.min.css
            ├── jquery-ui.min.js
            ├── jquery-ui.structure.css
            ├── jquery-ui.structure.min.css
            ├── jquery-ui.theme.css
            ├── jquery-ui.theme.min.css
            ├── LICENSE.txt
            └── package.json

  • Copy the the whole folder to /var/www folder

    pi@raspberrypi:~$ cd web-location
pi@raspberrypi:web-location$ cp -r greenwall /var/www/

  • Configure available Apach2 config file
    Alternativaly you can copy the green-wall.conf file, found under the web-config folder to the /etc/apache2/conf-available folder on the Raspberry pi

    pi@raspberrypi:~$ touch /etc/apache2/conf-available/green-wall.conf
 
WSGIRestrictStdout Off
WSGIApplicationGroup %{GLOBAL}
<VirtualHost *:80>
    ServerAdmin [email protected]
    ServerName www.greenwallsite.com
    ServerAlias greenwallsite.com

    ErrorLog /var/www/greenwall/logs/error.log
    CustomLog /var/www/greenwall/logs/access.log combined

    WSGIDaemonProcess greenwall user=pi group=pi threads=5 python-home=/var/www/greenwall/python/env
    WSGIProcessGroup greenwall
    WSGIScriptAlias / /var/www/greenwall/python/greenwall.wsgi    

    <IfModule dir_module>
        DirectoryIndex index.html
    </IfModule>

    Alias /greenwall/ /var/www/greenwall/
    <Directory /var/www/greenwall>
        Order allow,deny
        Allow from all
    </Directory>

</VirtualHost>

  • Configure enabled Apach2 config file

    pi@raspberrypi:~$ ln -s /etc/apache2/conf-available/green-wall.conf /etc/apache2/conf-enabled/green-wall.conf

  • Install mod_wsgi

    pi@raspberrypi:~$ sudo apt-get install libapache2-mod-wsgi python-dev

  • Enable mod_wsgi

    pi@raspberrypi:~$ sudo a2enmod wsgi

  • Restart Apach2 service

    ~~pi@raspberrypi:~$ sudo /etc/init.d/apache2 restart~~ 
pi@raspberrypi:~$ sudo systemctl restart apache2

Services on PI

CAM

sequenceDiagram
participant Cam
participant PI
participant WEB browser

    loop CamRegister
        Cam->>PI: POST /cam/register
        PI->>PI: register
    end

    loop AutomaticSaveFrame
        Cam->>PI: POST /cam/save/frame/camId/<camId>
        PI->>PI: save file
    end

    loop GetRegisteredCams
        WEB browser->>PI: GET /cam/captureList
        PI->>WEB browser: gives back the registered cams
    end

    loop SaveCaptureByRequest
        WEB browser->>PI: GET /cam/capture/url
        PI->>Cam: GET /capture
        Cam->>Cam: take photo
        Cam->>PI: send back photo
        PI->>WEB browser: gives back the url to the photo 
    end

    loop GenerateVideoFromFrames
        WEB browser->>PI: POST /cam/construct/video {camId,startDate,endDate,fps}
        PI->>PI: construct the video in the background
    end
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LAMP-PUMP

SENSORS

Port forwarding

Why do we need it? Because in development/test phase I use the stand alone WSGI server to receive REST requests from the Sensor Stations and Control Stations. The stand alone WSGI server uses port 5000.

But later, I use the integrated WSGI in the Apache server, instead of the stand alone WSGI. That means, the port changes to 80. But I do not want to change the code all the time in the Station modules, when I change the WSGI. To make it work in both case I have to do a port forwarding. If the Central Controler Unit receive a rest request to port 5000, it should be mapped to port 80 instead.

    root@raspberrypi:~# echo "1" /proc/sys/net/ipv4/ip_forward
    root@raspberrypi:~# iptables -t nat -A PREROUTING -p tcp -d 192.168.50.3 --dport 5000 -j DNAT --to-destination 192.168.50.3:80
    root@raspberrypi:~# iptables -t nat -A POSTROUTING -j MASQUERADE

The firewall should look like this:

    root@raspberrypi:~# iptables -t nat -L --line-numbers
    Chain PREROUTING (policy ACCEPT)
    num  target     prot opt source               destination         
    1    DNAT       tcp  --  anywhere             192.168.50.3         tcp dpt:5000 to:192.168.50.3:80

    Chain INPUT (policy ACCEPT)
    num  target     prot opt source               destination         

    Chain POSTROUTING (policy ACCEPT)
    num  target     prot opt source               destination         
    1    MASQUERADE  all  --  anywhere             anywhere            

    Chain OUTPUT (policy ACCEPT)
    num  target     prot opt source               destination

Unfortunatelly this settings will disappear after a reset, so you have to make it persistent.

    root@raspberrypi:~# /sbin/iptables-save > /etc/iptables/rules.v4
    root@raspberrypi:~# cat /etc/iptables/rules.v4
    
    # iptables-persisten was already installed
    # make sure the service is enabled
    root@raspberrypi:~# sudo systemctl is-enabled netfilter-persistent.service
    enabled
    
    # if it is not, then enable it
    root@raspberrypi:~# sudo systemctl enable netfilter-persistent.service
    
    # get status
    sudo systemctl status netfilter-persistent.service

ky040 - rotary encoder

To enable/configure the rotary-encoder device tree overlay, simply put something like the following into /boot/config.txt (with the encoder connected to pins 5 and 6 on the Raspberry Pi) While you’re at it, you might also want to add the middle button as a key (mine is connected to pin 13):

  • enable rotary encoder 
    pi@raspberrypi:~$ vi /boot/config.txt
   dtoverlay=rotary-encoder,pin_a=5,pin_b=6,relative_axis=1
   dtoverlay=gpio-key,gpio=13,keycode=28,label="ENTER"

After a reboot you’ll have a new device in /dev/input/ for the rotary encoder. You can use the evtest tool (as in evtest /dev/input/event0) to look at the events it generates and confirm that it reacts perfectly to every turn of the encoder, without missing a movement or confusing the direction.

  • Here is an example, shows how to read the output of the rotary encoder. 
    from __future__ import print_function
import evdev
import select

devices = [evdev.InputDevice(fn) for fn in evdev.list_devices()]
devices = {dev.fd: dev for dev in devices}
value = 1
print("Value: {0}".format(value))
done = False

while True:
    r, w, x = select.select(devices, [], [])
    for fd in r:
        for event in devices[fd].read():
            event = evdev.util.categorize(event)
            if isinstance(event, evdev.events.RelEvent):
                value = value + event.event.value
                print("Value: {0}".format(value))
            elif isinstance(event, evdev.events.KeyEvent):
                if event.keycode == "KEY_ENTER" and event.keystate == event.key_up:
	        print("Enter")

2x16 LCD display

  • In the Raspberry Pi run the "Raspberry Pi Configuration" application and undert the "Interfaces" tab, Enable the I2C
  • Connect the pins of LCD display to the corresponding pins of RP
    • GND -> GND
    • VCC -> 5V
    • SDA -> SDA1
    • SCL -> SCL1
  • Check th eaddress of the I2C box on the RP 
    pi@raspberrypi:/var/www $ i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- 27 -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --

Wiring

                                         
   Raspberry PI   LCD    Rotary                                         
   ____________________________                                         
   pin Function                                         
     3 GPIO 2     SDA                                               
     5 GPIO 3     SCL                                                        
     4 5V         VCC                                              
     9 GND        GND                                   Rotary encoder
                                                     _______________
     2 5V                +                          /        _       \
     6 GND               GND                       |     /       \    |
    29 GPIO 5            CLK                       |                  |
    31 GPIO 6            TD                        |    |    o    |   |
    33 GPIO 13           SW                        |                  |
                                                   |     \       /    |
                                                   |         -        |
                                                   |   C           G  |
     Raspberry PI W Zero                           |   L  T  S     N  |
    __________________                             |   K  D  W  +  D  |
   /     |      |     \                            |                  |
  |      |      |      |                           |   o  o  o  o  o  |
  |       ------       |                            \__|__|__|__|__|_/
  |             1  2   |                               |  |  |  |  |
  |             o  o-----------------------------------|--|--|--'  |
  | .-----------o  o------------------------.          |  |  |     |
  | |  .--------o  o-----------------------------------|--|--|-----'
  | | |         o  o   |                    |          |  |  |
  | | | .-------o  o   |             .-----------------'  |  |
  | | | |       o  o   |             |      |             |  |
  | | | |       o  o   |           .----------------------'  |
  | | | |       o  o   |           | |      |                |
  | | | |       o  o   |         .---------------------------'
  | | | |       o  o   |         | | |      |
  | | | |       o  o   |         | | |      |
  | | | |       o  o   |         | | |      |
  | | | |       o  o   |         | | |      |
  | | | |       o  o   |         | | |      |          LCD Display
  | | | | .-----o  o   |         | | |      |     ____________________
  | | | | | .---o  o   |         | | |      |    /      S  S  V  G    \ 
  | | | | | | .-o  o   |         | | |      |   |       C  D  C  N     | 
  | | | | | | | o  o   |         | | |      |   |       L  A  C  D     |
  | | | | | | | o  o   |         | | |      |   |                      |
  | | | | | | | o  o   |         | | |      |   |       o  o  o  o     |
  | | | | | | | 39 40  |         | | |      |   |       |  |  |  |     |
   \|_|_|_|_|_|_______/          | | |      |    \______|__|__|__|____/
    | | | | | |                  | | |      |           |  |  |  |
    | | | | | `------------------' | |      |           |  |  |  |
    | | | | `----------------------' |      |           |  |  |  |
    | | | `--------------------------'      |           |  |  |  |
    | | |                                   |           |  |  |  |
    | | |                                    `----------|--|-'   |
    | | |                                               |  |     |
    | | `-----------------------------------------------|--|----'
    | `-------------------------------------------------'  | 
    `------------------------------------------------------'