This forum page starts with "Warning: You are in the Gambling section. You are likely to eventually lose any money..."
Simple math, flat rate profit:
Coinitrage "200% in 4 days" = 100% profit in 4 days = 365 days/4 * 100% = 9125 % in year.
If you invest for example 100 USD, you get 91.25 times profit after year - 9125 USD
It goes better, with cumulative 4-day periods continuous (re)investment through 1 year looks like:
4 days = * 2 times the original investment
8 days = * 4 times
...
40 days = 2ˇ10 = 1024 times the original investment
...
180 days = 2ˇ45 = 35184372088832 times
...
365 days = 2ˇ91 = 2475880078570760549798248448 times
It is possible to invest 91 times with 4-day periods in one year: 365/4=91.25
Here we assume that all the profit money gets reinvested back.
So, investing 100 USD gives much more in cumulative, Coinitrage way:
247,588,007,857,076,054,979,824,844,800 USD profit after one year.
In 2013 there was 10,000,000,000,000 USD in existence (cash, accounts, checks, money market funds, savings accounts, CDs)
Let's assume that latest moneyprints and economic growth doubled the amount.
Let's add all derivatives, futures and other stuff, multiply the sum to 100 may be?
2,000,000,000,000,000 USD in existence...
So, just invest the 100 USD, after year buy the world, Moon and Jupiter...

Early morning here, correct me if I made mistakes with numbers.
Calc made with USD - more realistic than abstract crypto values.