Mr. Bogle believes that a simple portfolio including only two funds, the Vanguard Total StockMarketIndex Fund and Total BondMarketIndex Fund would be sufficient for many investors.
To show this, I created and rebalanced several portfolios using the Vanguard Total StockMarketIndex Fund Admiral Shares (VTSAX) and the Vanguard Total BondMarketIndex Fund Admiral Shares (VBTLX).