Purpose:Illustrate how the center of mass affects the stability of an arch
Description:Identical blocks are piled up with successively greater fractions of their lengths (slightly less than 1/12, 1/10, 1/8, 1/6, 1/4, and 1/2, respectively, from bottom to top) extending over the edge of the preceding block, as shown in the photograph. Even though the top block is entirely over the edge of the base, the center of mass of the system remains above the base, so the configuration is stable.
The toy automobile is not inherently part of the demonstration, but one can be made available upon request. :)