//    ////    ////    ////    ////    ////    ////    ////    ////    ////    //
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 ///    ////    ////    ////    ////    ////    ////    ////    ////    ////    
//    ////    ////    ////    ////    ////    ////    ////    ////    ////    //
/    ////    ''''    ''''    ''''    ''''    ''''    ''''    ''''    ////    ///
    ////    ,%%%%%%%%%P X%%%%%%%%'%%%%%%%. "%%%%%%%2.     7%%%%P    ////    ////
   ////    (%%    )%%/  %%%'   %J;%%T  `%%% %%%'  %%%    /%%%%%,   ////    ////
  ////    ,,,,   .%%J  J%%       %%%    %%% %%K   %%%   /%W^q%%;  ////    ////
 ////    ////   /%%'   %%L      ,%%%  ,%%' %%%L  J%3'  /%%Y )%%; '///    ////
////    ////  ,%%%    /%%%%%J   %%%%%%%<  ;%%%%%%<'   /%%%%%%%%( ///    ////
///    ////  ;%%"    ,%%'      ?%%'   %%% %%%' '%%@  /%%%'  7%%% //    ////    /
//    ///' ,@%%"    ,%%c      ;%%%    %% %%%'  '%%% /%%%'   '%%% '    ////    //
/    ///  /%%%/    ,;%%@L   ,%%W%%;  ,%%%;%%L   ;%%%v%%I     %%%;    ////    ///
    ///, L%%%%%%%%%%,'W%%%%%%% %%%%%%%%'c%%%%)   \%%%)%     L%%%%J  ////    ////
   ////    ,,,,    ,,,,    ,,,,    ,,,,    ,,,,    ,,,,            .///    ////
  ////    ////    ////    ////    ////    ////    ////  by svofski ///    ////
////    ////    ////    ////    ////    ////    ////    ,,,,    ,,//    ////    
/    ////    ////    ////    ////    ////    ////    ////    ////    ////    ///


              A computationally intensive demo for Vector-06c
                      presented at Retrograd 2025


  Requirements:
  ~~~~~~~~~~~~~

  An unexpanded Vector-06c (64K RAM, VI53 sound)


  Credits:
  ~~~~~~~~

  Code, music, graphics     svofski
  Maths optimisations       ivagor
  
  Based on shadertoy by iq/Fabrice/GregRostami/TomCat/fb39ca4
  see https://www.shadertoy.com/view/4lVXWw

  Initially a curiosity to test z88dk maths capabilities. Unoptimised 
  floating-point version used to take about 136 minutes to compute.
  A trick here or there and custom tailored maths routines by ivagor
  helped bring this time down to under 3 minutes.

  Thanks for your patience.


  ~ svofski 2025

  https://github.com/svofski/v06c-torus-zebra
  https://caglrc.cc