To study the importance of rotational modes of failure, the authors constructed physical models and tested them at different orientations. The study was carried out in three steps. First, a physical model was built consisting of two different tetrahedral block assemblies that could be placed on a tilt table. By systematically varying the orientation of the assembly on the tilt table and the slope angle of the tilt table, the block was tested to see how it would behave from rest, and each test was videotaped for subsequent analysis. Next, the physical model tests that exhibited rotational failure modes and tests with similar block orientations were analyzed for stability analytically assuming sliding and lifting modes only. Finally, the physical model test results were compared with the analytical results. The results of the physical model tests showed that the block failed by rotation in some cases, and in some of these cases, the analytical solution predicted a stable block. The results of this study suggest that rotational modes of failure may be the critical failure mode in some cases and should not be ignored.