Concurrency

,'.....',,;lk0XNNNNNNXKOdoOXNWWWWWWWMMMMMMMMMMMMMMMMMMMMWWWWWNNNXXKOkdolox0KXNNWWWWWWWWWWWWWWWWWWNNNNWWWWWWWWWWWWWWWWWWWWWNNNX0dlllcclllllllllllllcccccc::;;,'...   .....''......'o0NWWWMMMMMWWWWNNNWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWX0lcdOKNWWWWWWWWWWNNXXXXXXKK0kxdddkO00KKKKK0000OOOkdl;
,'.....'',;cx0XNNNNNNXKOdoOXNWWWWWWWWWWMMMMMMMMMMMMMMMMWWWNNKOkOOkxdolloodOKXNNWWWWWWWWWWWWWWWWWWNNNNWWWWWWWWWWWWWWWWWWWWWNNNX0dlllcccllllllllccccccc::::;;,'....   .............'l0NWWWMMMMMWWWWNNNNWWWWWWWWWWWWWWWWWWWWWWWWWWWWNXOc:oxOXNWWWWWWWWWNNXXXXXXK0OkxdddkO00KKKK00000OOOkdc;
;'......',;cx0KXNNNNNXKOdlkKNWWWWWWWWWWWWWWWWWWWWWWWWWWWWWXOc',;::::clllodOKXNNWWWWWWWWWWWWWWWWWWNNNNNWWWWWWWWWWWWWWWWWWWWNNNX0dlllccccccccccc::::::;;;;;,,'.....   .............,oKNWWWMMMMMWWWWNNNNWWWWWWWWWWWWWWWWWWWWWWWMMWWWNXk:,:ldkKXNNWWWWNNNNNXXXXXK0OkddddkO00KKK0000OOOOkxoc,
;,......',;cdOKXNNNNXX0kdlxKNNWWWWWWWWWWWWWWWWWWWWWWWWWWWNKx;;:clcc:cclllokKXNNWWWWWWWWWWWWWWWWWNNNNNNWWWWWWWWWWWWWWWWWWWWNNNX0dllcccc:::::;;;;;;;;,,,,,,''.....     ............;xXNWWWWMMMWWWWWNNNNWWWWWWWWWWWWWWWWWWWWWWMMMWWWWNO;'',;:ldk0KKXXXXXXXXXXXXK0OxdddxkO00KKK000OOOOkkdl:'
;,......'',:ok0KXNNNXK0kocd0XNWWWWWWWWWWWWWWWWWWWWWWWWWNNXOdoxkOOOkdocccclx0KXNNNWWWWWWWWWWWWWNNNXXXNNNWWWWWWWWWWWWWWWWWWWNNNX0dlllccc::;;;,,,,,,,,,,''''''.....     ............cOXNWWWWWWWWWWWNNNNNNNWWWWWWWWWNNNWWWWWWWWWMWWWWNN0:''','''',:ldkO0KKXXXXKK0OkxddddxOO00000OOOkkkxxoc;.
;,'......',;cdOKXXNXXK0kocd0XNWWWWWWWWWWWWWWWWWWWWWWWNNXKOkxk000KKK0Odc::cdk0KXNNNNNNNNNNNNNNNNXXKKKKXNNNWWWWWWWWWWWWWWWWWNNNX0dccc::::;;;;,,,,,,,,,''''''''......   ...........'ckKNNWWWWWWWWNNNNNXXNNNNWWNNNNNNNNNNNWWWWWWWWWWNNXOl::::;;;;;;;:ldxkOO000OOkkxdooooddxxxxxxxdddooolc;'.
;,'......',;cdOKXXNNXXKOdlo0XNWWWWWWWWWWWWWWWWWWWWWNXK0kdlldO00KKKKK0kl;;:ox0KXXNNNNNNNXXXKXXXXKK0O00KXXNNNNXXNNWWWWWWWWWWNNNXOo:;;;;;;,,,,,,,,,,,,''''''''''...................';oOKXNNNNNNNNNNXXKK0KKXNNNNNXXKKKKXXNNNNNWWWWNXKkdlllllllcccccccclloooooooolllcccccccccccc:::::::;;,'..
;,'.......',cdOKXNNNNXK0xloOXNWWWWWWWWWWWWWWWWWWWNNKkl:;,,,cx00KKKK0Oxl;;:oxO0KXXXNNXXXKK000KK000000000KKKK000KNNWWWWWWWWNNNNXOl;,''''''''',,,,'''''''''''''''''.................';cdkO000KKKKKKK0OOxdxO0KKKK0OOOkO0KXXXXXXNNXKOxlllllllllllccccccccccccccc:::::::::::;;;;;;;;;;,,,,'.. 
;,'.......'':dOKXNNNNXX0kllOXNWWWWWWWWWWWWWWWWWWNX0d;'''....;okOOOkxdlc;;:ldk0KKXXXXXXKK0000000000K00OOOOOOOO0KNNWWWWWWWWNNNXKkc''.......'''''''''''''''''''',,''''''..............';:lllcldxkkkkxdollodxxkkkxkkkkOO0KKK00000Okxolllllllllllcccccccccccccccc::::::::::;;;;;;;;;,,,,'..  
:,'........':okKXXNNNXK0kllkKNNWWWWWWWWWWWWWWWWNXOo,..........,cclc::;;;;;:ldkOO0KKKKKK0OOO000000000Okxxkkxxk0XNNWWWWWWWNNXXX0d;'........'''.............'''''',,,,,,''............'',;,,,,;clllllc:clooddddddxxxkOO000Okkkkkxxdolllllllllllccccccccccccccccc::::::::::;;;;;;;;,,,,'..  
:;'........';lxOKXXXXK0Odccd0XNNWWWWWWWWWWWWWNNKk:.............',,,,,,,;,,,;clooxxxkkkkkkxddkOOOkxxddoooddoldOKNNNWWWWNNNXKK0xc,'.......................''''''',,,,,,''''........'',,,,;,,,,,;::::;::clloooolllodxkOOOkxdddxxxxdlllllllllllllcccccccccccccccc::::::::::;;;;;;;;,,,'...  
:;,'........,:oxkO00OOxoc;,cdOKXNNNNWWWWNNNNXKkl'...............',,,,,,'''''',,;;:::cclllc::loooollc:;;:::::cx0XXNNNNNNXK0Okxl:,'......................''''''''',,,,,,,,'.......'',,,,;,,,,,,,,;,,,;;::ccccc:;;:cldxxxdolcodxxdolllllllllllllllccccccccccccccc::::::::::;;;;;;;;,,'..   
:;,'........',;cloddol:;'...,coxO00KKKKKK0Okdc,.     ............'''''.............'',;;,,,,;;;;;;,,,,,;;:::;cdOKKXXXXK0Oxddoc;'......................''''''''''''',,,'''''....''',,,,,,'''',,,,,,,,,,;;;:;;,,,;;;::cc:;;:odxxdolllllllllllllllllccccccccccccc::::::::::;;;;;;;;,'...   
:;,'..........'''',,,'..........'',,,,,,,,'...          ...................................'',,,,''',;;:cccc::coxkOOOOkxdollc;,'.......................''''..........'''.......'''''''''..',,,,,;;;;:ccc::;,,,,,,,;;,,,,,codxxollllllllllllllllllllccccccccccc::::::::::;;;;;;;,,'...   
:;,'.........................     ..........            ...................................'',,,,,,;::clodddooloooooolllc:;,''..................................................'''''.....',,,;;::::cclcc:;;,,,,,,,,,,,,:odxxdolllllllllllllllllllllccccccccccc:::::::::;;;;;;;,,'...   
:;,'.........................      .........          ....................................'',;;::;:cccloodxxdooooolllc:;,''........    ................''.........................'''.....'',,,;:::cclllc:;;,,,,,,,''..':odxxdolllllllllllllllllllllllcccccccc::::::::::;;;;;;,,'....   
:;,'.........................      .......................................................',;::::::clllloddddollllcc::,,''........       ............''''''......................'''''.....'''',;;::cllc::;;,,,,,,,''..,codxdooolooooooooooooolllllllllccccccc:::::::::;;;;;;;,,'.......
:;,'........................       .........................................'''..........'',;:cc::;:cccllooolllllccc:::;,'............  .......',,,''''',,'''...................''''''''.......'',;;:::::;,,''',,,,''.';lddxdooooooooooooooooooolllllllllcccc::::::::::;;;;;;,,;,,,,,;::
:;,'........................      .........'';clc:;''''''''''..............'''''..''''''',,;;cccc:::;;,;;;;;;;::cccccccc:;,''..............'';clllllc;,,,,,,''.......'''''''''''',,,'''''......'',,;::::;,,,''',,,,,'',codxxdoooooooooooooodddooooolllllllllllcc:::::;;;;;;;,;:::clloddd
:;,''...............''........   .......'',:dO000K0Oo;;,,,,,''............'',,,',,;;;;;,,,;;:ccllc::;;,,,,,,;;;::cccclllc::;,,,,,,,,''''',,,;loooooool:::;;;;,,,'''',,,,,,,,,,;;;;;;;;;,,,'''''',,;;::::;;,,,',,,,,,,;codxxdooooooooooodddddddddxdddolloooddddddolc:;;;;;;,,;:cloodxkkkk
:;,,'..............''''''.............'',,:x00KKKKKKKd:;;;;,,''...........'',,,;:ccccccc:::::ccccc:;,,,'',,,;;:::cccccccc::;;,,,;;;;,,,,,;;;:loddddddl::::;;;;;;,,,;;;;;;;;::::::::::::;;;,,,,'',,,;:::;;;,,,,,,;;;;;:ldxxxdooooooooodddddxxxxxkkkxxdoooodxxkkOOkxoc:;;;;;,;;:llodxkOkkk
:;,''..............'''''''.........'',,,;;:x0KKKKKKKKk:;;;;,,'''...........'',,:clllllollccc:ccc::;,,'''''',,,,;;;;,,,,,,,,,,,,,;;,,,,'''',,,;clllll:;,;;;;;;;;;;;;;;;;;;:::::::::::::;;;;;,,''''''',,,,,,'''',,,,;;;:odxxxdooooooooddddxxxxxxkkOOkxdoooodxxkOO0Okdl:;;;;;,;:cloddkkOOkk
:;,'...............''''''........''',,;;;;:ck0KKKKKKkc:;;;;,,''''..........''';:looddooolcc::::;;,''''''''''..''...............'''.....................'''''''',,,,,;;;;;;;;;;;;;;;;;,,,,''''...............'''''',,,codxxdoooooooddddxxxxkkkkkOOOOxdooooddxkkOOOxoc;;;;,,,;:cloodxkOOOk
;;,'................''''''.....',,,;;;;::::::ldxxxdc:;;;;;,,,'''............',;clodxxxdolc::ccllc;'''''..........................................................'''',,,,,,,,,'''''.................................':oddxdooooodddddxxxxkkkkkO00OOxdooooddxxkkOkdo:;,,,,,,;cllooodkOOOO
;;,'...............''''',,,,,;;:::cclllcccccc:::::;;;;;,,,,,'''.............',;:lodxkO000KXNNNNNNNKko,'''.............................................................''''..........................................':ldddooooodddddxxxxkkkkkkO00Okxooooodddxxkkxdl:,,,,,,;:cllollodkkOO
;,,'..............'',,,,;;;;:::cccllllllllcccccccccccc::;;,,'''.........';cldkO0XNNNNNNNNNNNXXXXXXXXXKd::;;;'......................      .........................................           .......................,codddoooodddddxxxxkkkkkkO000Okdoooooddddxxxdoc;,,,,,,;:cllllllodxkk
;,''..............'',,;;;::::cccllllollllllllloooddxxxddolc::;;,,;:lodO0KXNNNNNNNXXXXXKKKKK00Okkdolc:;,'....  ..................          ...................................                .......................;lodddooooddddxxxxkkkkkkkO000Okdooooodddddxdol:;,,,,,;:ccllllc:clodd
::;,,''...........''',;;;;::::cccllllllllllooddxxkkOOOOkxxdoolodxkkxxddollod0XXXKOkdoc;,'..                      ..................       ...........................                                 ........... .':ldddooooddddxxxxkkkkkkkO0000Oxoooooddddddddol:;,,,,,;:cllllcc:;;;:l
lllcc:::;;;;;;;,,,,,,,;;;,,;;::::cccllllllloodxkOO00000Okkl;::;,''''''''''lc'..                           ....;c; ..................      ........................                                                .,codddooooddddxxxxkkkkkkkO0K00Oxoooooodddddddoc:,,,,,;:cllllcc:;,'.':
ddddddddooolllllcccccccccccclllloooddoooooooodxkkOO00OOkk:.                ',;..              ....         .. ...   .................      .....................                          .                       .;lodddoodddddxxxxxxkkxxxkO0K00kdollloooodddddoc;,,,,,;:cllllc:;,'...'
kOOOOkkkkkkxxxxddddddddxxxxxkkxkkkOOkkxkxxxdddxxxxkkkkxd'                    .::.    ....',,'.....       ......'''... ...............      ...................                      .......                ..... .':odddodddddddxxxxxxxxxxdxO000Okollllllloodddolc;,,,,;:clooolc:;'.....
000000000OOOOOOkkkkkOOOO0000000000K000OOOOkxxxxdddddddc.                        ...   . .    .......',,;,,,,,;:cllooc'. .............       ..................                  .............             ........;loddddddddddxxxxxxxxxdddxO000Oxollccccclooddol:;,,,,;:loooolc:,'.....
000000000000000OO00000KKKKKXXXKXXXXXKKKKK0OOkkxxdddddc.                           ,;..   ,,,',;;;;:::lloodxxkOkOkxxkkdc;....,,'.......             ..........                .................            .......':ldddddddddddxxxxxxxxxdddxO00Okdllccc:::cloddol:,,',,:cloooll:;'......
KK000KKKKKKKKK0000KKKKKXXXXXXXXXXXNXXXXXXXKK00Okkxxkx.                             .,;..  .;ccldddxxxxOOOOOOOOOOOOkkOOOOkl;..',''...........          .....                    ..............               .....,codddodddddddxxxxxxxxxxddxO00Okdllccc:::cloddoc;,'',;:cloollc;'.......
KKKKKKKKKKKKKKKKKKKKKXXXXXXNNNNNNNNNNNNNNNXXKKK0OOOO:                 ....           .;,..  .oxkkkkkkOOOOOOOOOkkxxkkkkkOOkkdl,..'..........................                       ..........                   ..:ldddddddddddxxxxxxxxxxxddkO0OOxollccc:::clodolc;''',;:cllllc;,........
KKKKKKKKKKKKKKKKKKKKXXXXXXNNNNXNNNNNNNNNNNNXXXKK000O.              ;oxOxcc;.           .,;..  ,dOkkOOOOOOkkkkkoododddxkxxkO0OOOl..'.........................                 ..............                    .,codddddddddddxxxxxxkkxxxxxO000Oxollcccc:cclodol:,''',:cllllc:,'........
KKKKKKKK0KKKKKKKKKKKKXXXXXXXXXXXNNNNNNNNNNNNNXXKKK00.            .O0OO0XKol,.            .,,..  ,dkkkkOOkkkOOOOkolllodkOkxxkOOko;. .,:::::;;,,'..............                ........................         ..;lodddddddddddxxxxkkkOOOkkO0K00Oxollllllclooddol:,'',;:clllc:,'.........
KKKKK000000000000KKKKKKXXXXKKKKKXXXXXXNNNNNNNNXXKKKK,            oK:cck0KOo:.              .',..  'dOO0000OOOOOkOkxllololooddoool:'. .o00000OOxoc:;,'.......               .............................    ...,codddoodddddddxxxxkkOO0000KKKK0kdllcccccclodxdoc;'.',:clllc:;'..........
KKKK0000000000O00000000KK00000000000KKXXNNNNNNXXKKK0k.          .KKOxO0KOkc'.                .''..  'xOOOOOOOkkkkOOkoc::::clolllodoc'. .d0000Okddddol;'..... .............   ..................................;lodddooddddddddddxxkkOOO00KKK0Oxl::::::::codddoc;'.';:cllc:;,...........
KKKKK00000000OOOOOOOOO0OOOOOOkkkkkkkO0KKXXNNNNNXXXXK0d.         dKKKKKKOOd,.                   ..'..  'okkkkOOOOOOOOOkocclodxOkollc;..   .;::;;loxxxol:;'',;codddddddxddol:;'.................................':ldddoodddddddddddxdxxxxkkO000Oxl;,,,,,;;;:loddl:,..,;clllc:,'...........
KKKKKK0000000000OOOO000OOOOOOOOO0OOO0KXNNWWWWWWWWWWK00d.       .0KKKKKKK0c                       ..'..  'dOOkkkOOOOOOOOOOxol:,..       ....,,,,::ccclxkOkxxkO0KKKKKKKKKKK0Okxdl:,.................       .....,codddoddddddddxxxxxxxxddxkO0K0kdl;,,,,,,;;:codol;'.',:cccc:,'............
KKKK00KKKKKKKK00000OOOkkxxxkO0KKKXXXXNNNNWWWWWWWWWWK000k.      lKKKKKKKKx.                          .'..  'looll:coc;'..       ....',,::;::;;,,,,,';lxOOOdc:clooooooooooooodxkkdl:'..............           ..;lodddodddddddxxxxxxxxxxxkOKKK0Odc,,,,,,,;;:clolc;'.',;:cc:;'.............
000000KKKKKK000OkkxxdddddddxxkO0KKXXXXXNNWWWWWWMMWWXK0KXO,    .0KKKKKKK0c                 ..          ....  ...         ....',,':;,;;,lkd::llc;,,:odkOOkxdolllc:::lc;......;oooocl:,.........,;;::::::;;;,'..;codddoodddddddxxxxxxxxxxkO0KXK0ko:,''',,,,;:cllc:;''',;::;;,'..',;:ccllcc:
000OOOOOOOOkkOOxddddddddxxxxxkkkkkOO0000KKXXXNNNNNXK000OOOo'  cKKKKKKKKx'                               ....     .....''',o;';,,;oo;loxO,Okdo::::;c0XXXXXXXXXXXKKK0Okdc,,'',:ccloddocccc:;,:x0XXXXXXXXXXXKKKKK0OxxdoodddddddxxxxxxxxxkO0KKXK0ko;,,,,,,;;::cccc:;,,;;;;;;;,,:ldxkOOOOkkkk
dddooooooooodkOkddddddddddxxxxxxxxxxxxxxxkkkkkkkkk0K0000OOkkxl0KKKKKKK0c.                                 ........'o;'::;,cdoloddc'ooc::;;;,:ccl:;:;lOKXXXXKK0OOkxxkOOkdlcclodkkOOOOO0KK0OxxOKXXXXXXXXXXXXXXXXXK0kxxdddddddddxxxxxxkOO0KKKKK0Oxdoooolllccccccc:::::c::::::codkO00KKKKKKK
ooooooooooooddxdddddddddxxxxxxxxxxxxxxxxxxxxxxxxxx0KKKKKK000O0KKKKKKKKx'                                    .......cOxldkkk'cl:,:,,;,l0cc::;;dkkkd.;:;:dO0Oxolc:::lkOOkxxddxkO000OO0KXNNNXXXXXXXXXXXKK000OOOOKXXX00OkkkkOOOOkxxdddxkO0KKKKKKKK00000000OOOkkkxxdddolllcccccloodxxxO0KKKXX
oooooooooooooddddxxxxxxxxxkkkkkkkkkkkOOOOOkkkkkkkk000KKKKKK000KKKKKKK0c..                                     .......,;,';,,',,d0c;c;,:kkoddk;;:;',;:::,:xKxoololclkOxooxxkkOO00KKKXXNNNNNNNNNNNNNNNNNNXK0KKKKXXXK000000KXKK0kxddddkO0KKKKKKKKKKXXXXXXXKKKK0Okxddolcc::ccccccccclok0KKXX
lllllloooooooodxxxxxkkkkkkkkkkkOOOOO00000OOOkkkkxx00KKKKKKKkdxO0KKKKKxcc,...  ..                                ......'',Ooc;,,'cOOkxxd,;clcc;;:;:cccccc;,:od;ckOkdclOxdxxkxk0KXXK0kxkO0XNNNNNNXXXXXXNNXKKKKKXXKKKKKKK00KXXKOxdooodxk00KKKKKKKKKKKXXXXKK0Okxdlc::;,,''',,,,,,,;;;:ok0KKK
llooooooooooodxOOOOOxxxkkkOOOkkOOKXNNNNXK0OOkkkkxx0KKKKKKKK00kdxk00KKllcdko:'......                                .....''cxdddko';cc:c;,,;o0locc;,;:::;,;;,..,;:;cl:cOddddxO0K0kxdddddx0XNNXK0Okkkkk0KXXK0OOO00K00O00OO000kxdooooodkO0KKKKKKKK0000000Oxoc:;,''''',''........''''':dkOOO
odddxxkkdoooooxk000OOkkkkkkkkkOO0KNNNNNXKOkkkkxxddOK0KKKKK00OkkxddxOKdoxxxkOOxl;''....                               .. ..'',;:c:;,;,xKk::',;dxdood,;,;;lodo;....:ll::xdddxkkxxdxxxxxxxxkOO0K0OkkkkkOOOKK0xxxkOOOOOkkkkkkkxdooooooodxkO0KKKK00OOkkxddlc;,'''',,,;;;;;;,,,,,,,;;;;;:odddo
XXXXXXXXKOOOOOOOOO000000OOOkkkkOOO000OkxddddooooookKKKKK0000Okxddxddxdl:loddxkOkdl;,''..                               .. ..'';Ok:ol:,:dkkodl,,;;:c:::;lO0OOkd'...:l:dxoxxkxdodk0XNNNKO0NNKNWNKOOOOO0KK0kkxxxk00OkkkkxxkkkxxxxxxxxdddxkOOO0OOOkxdl:;'........',;:cccccc:::cccc::::cloooo
K000000K0kccc::::cllllldxkOO000OOOO0KX0kxoolllllllxKKKKKK0000OOkxxdddodoooooooooolooc;,,'..                              .....''cxdoool,,,,;c;:,,lOd:o;,;ldddl'....;xxldxkkxdxOXWWWWWNK0XX00000OOO00KKK0OkxxkkKK0kkkkkkxxkk00KKKKKK0000000000Oxoc;''...''''...,;::::::;;;;;;;;,,,,;::::l
kkxxxddooollllodxxxxxkkxxdolcoxkOOxdxkkxdooollccccdKKKKKK0000OOOkxdooloddolloooooollloc:;,,''.',.                          .....'',,,::::;,o0dldc,;lxddxo,,,''',,,,,,:oddxddxkKNWWWNXK00000KXK00OOO0000OOkkxxxkOOkkOOkkkkkOKKXXXXXXXXXXXXXXXXKK0Okkxxxddoolc:ccccc::;,''...............'
;cccccllllooooodxkkOO0000KK0OxoccoxkkxooooddollcccoKKKKKK0000OOOOOOkxdooddxkkkkkxxxolx0xocooddddd..                     .:dO0x:,;,',,kOc;c,,:dOkxdo,,,,co,;::,',,,,,,,;oxxxddxkkOkxdddxkkkOOKXKOkkkkOOOkkkkxdddxxxxkOkkkkkkOO0000KKKKKKXXXXXXXXXXXXXXXXKKK00OOOOxdllcc:;,,''............
,looooooooooooodxOO00KKKKKKK0kxdolcccoxkxxxdoollllo0KKKKKK00000000OOkkkO00000OO00OOkxoOXKOkxkkkkl'...                 .xKK0O0KKd''..'':xxddxo,,,,cl,;,,cOx:do:.......',,odolllcccccclloddxxxOK0OkxxkkkxxxdddooodxxxkkkkxxxxxxddxxxkkkkkOO000KKKXXXXXXXNNXXXXKK0Okdlllllllc:;'.....     .
,;loooooooooooooxkO0000KK000OxdolllllcccldkxxooodxOKKKKKKKKKK0000000KXKXXXXKOkOOOOOkxdcdKXKK0OOkc:;'..                x00;.,ck00d... .',,,;l:,;,,oKxoc:,,ckdlcoc''''''''.cllclooollllloddddxxkOOkkkkkxxxdolclloxxxdxxxxdxxkkkkkkkkkkkkkkkkkkOO00KKKKXXXXXXK0kxdl:,,,;:::;,'....        .
.,cllllllllllllodxOOOOOOOOOkxdoolllllllllc:cdxxxOXNNKKKKKKKKK00KKXNNNNNXXKO0OOOOOkkxxdl:;oOKXKKOo,..                 ,000c,'dOO0k,'.   .',;kOlokc;,oOdl:c:',;;,,,,''.....,oodk00OkkxdddxxdxxkkkkxxxxxdxxdolloodddxxddxxxkO0000000OOOOOOOOOOOO000000KKKKKK0kdlc:;'....''.......        ..
 ':llllllllllllooxkOOOOOkkkxdooooolllllllllc::cdO0XNXXXXKKKKKKNNNNNNNNXXXKK000Okxxxxxddl:;:cxkO0KKxc'.    ...        k000000OOOkd.       ..':xklc;cc';::,,,''''....     .cloxO000OOkxkkkkxkOOkxddddddollloooddxxdddddddxkO000000000OOOOOOOOO000000KKKKKKKOdl::;'........................
 .clllllllllllllloxkkkkxxdddoooooolllllllcccccc::lxO0XXXXXXNNNNNNNNNNXKO0K0OOkkxxdddddddlc::::.,,cdOOOkdc:,;;'.     :00000K000Ox;           ..,:cc;,,,,'''...       ....;:clodddxxxxxkkkxxxkOOxdddddoooodddlccclllodxdddkOO00O000OOOOOkkkkkOOOO0000KKKKK0koc::;'.  ............',;;:::::
  .lc:::;;,,,''',:looolllllloooolllllllccccccccccc::lk0KNNNXXXXNNNNXKOO00OOkkxxxxddodddddolc:.      .';codxxdoc;.. .O0000000000o.              ...''....       ....   ..',;:cccclodddxxxxxxkKXKdddoooooxO0Oxl:::cllodddxO000OOOOOOOOOOkkkkkkkkOOOO000000Odlcc:;'.         .....',:clllll
   ;c..........';:::::::::clllllllccccccc::::ccclc:oOxldO0XXOKK0KXXXK0Okdooxdccdddoddoodddool'             .,cxkdc,o0000000000k'                           ...        ...';:ccccloooddddxxxxOOxdddooooox0K0klccllllloddkO0000000OOOOOOOkkkkkkkOOOOOOO00Okdlcc:;'.         .......,:::ccc
   .c,........,:::::::::::ccccc::::;;;;,,,,,,;:cd0NWNNNOook0KOkOkk0K0Odcoocloccocllcoooolclolc.         ..',,''.:kO0000000000Oc                                     ..'..',:ccllllllooodddddddddooolc:::cc:;,;clc:;::cloddxkkOOOOOOOOkkkkkkOOOOOOOO00000Oxoc:;;'.  .....    ......,,;;;;
    .l......';cllcc:::::::::::;;,,,'''......'ckXNWWNNNXKX0olk0kO0000Okxlcooccc:c,:ooooc::ll:;'':l;'.',::cccccc:'O000000000000x.                                ..';cc;,'..',;:ccccllllloooooolllcc:::::::;,'''',,''''',,;;::cldxkkkOkkkkkOOOOOOO00000000kdc;,''..  ..............',,;;;;
     ;; ....';cccccccccccllllc:;,''''.......dKKK00KNNNNXK0KOllxOOOOkxllol:::l::clollc;::::;;:::oOkxxxkxxdoolllcdK00000000000O:                              ..',:coddol,......',;:::::::::::::;,,',;:cclllc:;,'.............',;:cllooddxxxxdddxkkkOOOOOxo:'.................'',;;:ccclll
     .c....',,;:cloooooodddddol:,''',,,;;;,,xKKK000O0KXXXKO0OkolxOOxlllc::c'coooll;;:::ccccccccdOOOOOOkkkkxdooc;:okOO0000000d,.                          ...';:codxkxxxkdl;....,;;,,'''''''''''''',;:::cloolc;'..................'',;;:ccclccccloooooooc:,,,,;;;;;;;;;;:::cccllloooooodd
      .:..'',,;:looooooooddddoc;,'''',,,;,,'c0KKKK00kxx0KK0OkxoolcxOkdol;;lloolc:;;::ccc::::cdxkkOO000OOOOkkxd:   'cdkOO000koOkl,..                  ..',;;::lxkkxollllox0K0o',clc::;,'''''''''',,;;:cclllllc;'...    ..     ........'',,;;:::cccllllllllllllloooodddddxxxdddddddddddodd
       ;,',,'',,;;:::::ccllll:;,'...........'d0000000Okxk000kxl::lclkOxoooollc;,,,;;::::::::dKK00kxxxxxxxkkkkxc......,coxO0OdOO00ko:'......... ....',;;;;:lodoc:,,,;;,'.,cx00k;cllollcc::;;;;;;,;::ccllllcc:;'...            ............'',,;;::ccllllooddddxxxxxxdddxxxxdddddddddddooo
       .:,'''''''''''',,,;;;;,,,''''''''''''',x0OOO0000OOOOkxdoc:::cclkkdc;:c:;,'''',,;;;:::o0KKKKKKKKK0Okxdooo:,'...''';cdkxxkkOO00kdc;,,,,;;;;;;:::ccclc:;,''''''''',,;;lxkkd:cllolllllccclcc:;:::::cc:;,'....             ...............''',,,;;:ccloooddddddddoooodddoodxxxxxdddddo
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;;;;;;;;;,,,,,',,,,,''''''''''',,,,,,,,,,,,'''.............. ....  ...................,kOc..':clodddddddddddddddddddddooooolooc'',,,;;;;::::::::::ccccclllllllllllllooooooooooooooooooooooddddddddddxxxxxxxxxxxxxxxkkkkkkkkkkxxxxxxxxxxxxxddxdddddddddddooddddddooodooooolllllllcccccc::
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,,'',,'''''..................'''',,,,,,,,,'''................................''''''.....dOx';llloodddoooooddddddddddooooooooool;;;;;;:::ccccccccccccclllooooodddddddddddddddddddddddddddddddddxxxxxxxxxxkkkkkkkkkkkkkkkkkkkkkkkkxxxxxxxxxxxxxxxxxxxxxxxxxddddddddooooooooooooollllllllll
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....................    ...'''''''',,,,,,'''...........................''................:OOodoodddxddddooooodddddddooooooollolccllllllllllooooooooooddddddddddddddddddddddddddxxxxxxxxxxxxxxxxxxxxkkkxxxxkkkkkkkkkkkkkxxxxxxxxxxxxxxxdddddddooooodddddddddddddddddddooooooooooooollllll

Polaris ERP

Polaris is a retail operations system that covers the parts teams touch all day: invoices, quotations, refunds, stock, customer credit, supplier purchasing, reporting, and the admin surface around all of that. It is the kind of product where a small mistake can turn into a stock problem, a bad balance, or a support mess by the end of the day. Tech Stack: Vue 3, Pinia, TanStack Query, Django, Django REST Framework, PostgreSQL, Redis, Celery ...

Go Load Balancer Dashboard

A load balancer written in Go with a real-time monitoring dashboard. It supports multiple balancing algorithms, health checks, and automatic failover. This was a learning project to understand Go’s concurrency model and network programming. Tech Stack: Go, WebSockets, HTML/CSS/JS Source: github.com/M-Hassan-Raza/go-load-balancer-dash Why Build This I wanted to understand how load balancers actually work—not just use them, but build one. Go’s goroutines and channels seemed like a good fit for handling concurrent connections, and the standard library has solid networking primitives. ...

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I Shipped a Race Condition That Double-Charged Customers (And Other War Stories)

Nobody writes blog posts about the bugs they shipped. The internet is full of “how I built X” and suspiciously empty of “how I broke X and spent 14 hours pretending it wasn’t my fault.” Here are mine. The Race Condition: Two Cashiers, One Item This one happened in Polaris, the ERP system I built for retail businesses. Real money, real transactions, real angry shop owners. The setup: two cashiers at different terminals. Both scan the same product. Both hit “Complete Sale” within 200ms of each other. The inventory says there’s one left. ...