Each fund's tile is its calendar-year total return by net asset value, with dividends and capital-gain distributions reinvested, as Vanguard publishes it on the fund's profile page. Those returns are after the fund's expense ratio, which for these index funds is a small fraction of a percent a year, so they sit slightly below the index each fund tracks. Cash is the 3-month Treasury bill and gold is the gold price, both from Aswath Damodaran's annual returns workbook, so those two carry no fund costs. The quilt starts in 2011 because Vanguard publishes the most recent fifteen calendar years; it stops at 2025, the last complete year in both sources. Annualized return is the compound (geometric) average of the fifteen yearly returns; the growth view compounds the same yearly returns from $10,000 at the end of 2010, before any taxes.
Every fund's yearly return was checked against a second source, the adjusted closing price in Yahoo Finance's price history (December to December).
The 60/40 tile is a real fund, Vanguard Balanced Index Fund (about 60% US stocks and 40% US bonds), not a computed blend of the other tiles.
This page illustrates history and arithmetic. It is not investment advice, and past returns do not predict future ones.
It illustrates the "Importance of Diversification" section of Index Funds in the personal finance guide.