Mechanical engineering
From Mounting methodologies to measure EUV reticle nonflatness (SPIE Proceedings 7470, 2009), by UW–Madison Professor Roxanne L. Engelstad's lab. Notice how Battula et al. explain the limitations of their findings, and identify specific future developments that would make their proposal more accurately testable.
The horizontal whiffle tree mount should have performed the best considering the kinematics of the 16 support points, as well as theoretically displaying the least amount of gravitational distortions. However, due to possible friction at the pivoted joints and the current tolerances on the whiffle tree system, there were difficulties in using this mount. At this time, the process of averaging the measurements taken at four vertical orientations appears to be the best approach.