Programming Crypto Blockchain Contracts (in Ruby) Step-by-Step Book / Guide. Let's Start with Ponzi & Pyramid Schemes...

Hello,

  I've started a new (free online) step-by-step guide / booklet titled:

  Programming Crypto Blockchain Contracts (with Ruby) Step-by-Step
Book / Guide. [1]
  Let's Start with Ponzi & Pyramid Schemes. Run Your Own Lotteries,
Gambling Casinos and more on the Blockchain World Computer...

  The first chapter about Ponzis & Pyramids is online with
ready-to-run contract scripts in ruby. Example:

  ##
  # a simple ponzy (scheme) contract
  #   last investor (or sucker) HODLing the bag
  #
  #  to run / test - use:
  #    $ ruby ./ponzi_simple.rb

  require_relative './lib/universum'

  class SimplePonzi < Contract

    def initialize
      @current_investor   = '0x0000'
      @current_investment = 0
    end

    def call
      # note: new investments must be 10% greater than current
      minimum_investment = @current_investment * 11/10
      require( msg.value > minimum_investment )

      # record new investor
      previous_investor   = @current_investor
      @current_investor   = msg.sender
      @current_investment = msg.value

      # pay out previous investor
      previous_investor.send( msg.value )
    end

  end # class SimplPonzi

  ###
  # test contract

  ## setup test accounts with starter balance
  Account[ '0xaaaa' ].balance = 1_000_000
  Account[ '0xbbbb' ].balance = 1_200_000
  Account[ '0xcccc' ].balance = 1_400_000

  ## (pp) pretty print all known accounts with balance
  pp Uni.accounts


  ponzi = SimplePonzi.new

  Uni.send_transaction( from: '0xaaaa', to: ponzi, value: 1_000_000 )
  pp ponzi

  Uni.send_transaction( from: '0xbbbb', to: ponzi, value: 1_200_000 )
  pp ponzi

  Uni.send_transaction( from: '0xcccc', to: ponzi, value: 1_400_000 )
  pp ponzi

  ## (pp) pretty print all known accounts with balance
  pp Uni.accounts


   Don't Miss the Investment of a Lifetime!
   May the Brave be Rewared with Riches! Happy coding with ruby!

   Cheers. Prost.

PS: Bonus points if you can point out how to "hack" the simple ponzi - that is,
how you can "invest" with a guaranteed pay out!

[1] https://github.com/openblockchains/programming-cryptocontracts

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