Replicate in sql server 2008

SELECT 'Ha'+REPLICATE('ha',20)

--    OUTPUT Hahahahahahahahahahahahahahahahahahahahaha

DECLARE @FirstString VARCHAR(MAX)

SET @FirstString = REPLICATE('A',4000)

SELECT LEN(@FirstString) LenFirstString;

--    OUTPUT 4000

DECLARE @SecondString VARCHAR(MAX)

SET @SecondString = REPLICATE('B',8000)

SELECT LEN(@SecondString) LenSecondString

--    OUTPUT 8000

DECLARE @ThirdString VARCHAR(MAX)

SET @ThirdString = REPLICATE('C',10000)

SELECT LEN(@ThirdString) LenThirdString

--    OUTPUT 8000 (HERE VALUE SHOULD BE 10000)

DECLARE @ThirdString VARCHAR(MAX)

DECLARE @ThirdSource VARCHAR(MAX)

SET @ThirdSource = 'C'

SET @ThirdString = REPLICATE(@ThirdSource,10000)

SELECT LEN(@ThirdString) LenThirdString

--    OUTPUT 10000

DECLARE @ThirdString VARCHAR(MAX)

SET @ThirdString = REPLICATE(CAST('C' AS VARCHAR(MAX)),11000)

SELECT LEN(@ThirdString) LenThirdString;

--    OUTPUT 11000