A stone hole was recovered from a stone used in the construction of a building in Wilmot S.D. The building was constructed in 1899, so the hole was made before that. This 3D model is based on a cross-section that was cut through the plug. This model does include the back side of the plug which contains the stone hole. As a result you get the appearance that you can actually see the hole from the inside out. Keep in mind that using this method that the wall of the hole is just one pixel thick. When viewing the hole from the back side you will notice that the hole was chisled at and angle to the surface of the rock.
You will also observe that the outside, bottom of the hole was not modeled. This is because that portion of the hole could not be reached from a sufficient number of camera angles.
Thanks to Judi Rudebusch for making this stone hole available for study.