Gutenstein optics

Looks from above like a stone really. Whether he fits unobtrusively into the landscape, of course, depends ddavon which stones otherwise so lying around. Experienced geocachers recognize the "model".
Weak point: the container on the bottom does not really. He falls by itself out again. Let alone that it would be watertight. I wanted to tuck a piece of paper in it. A4 was folded small always still too large, again folded and the resistance of the folded paper has rausgedrückt the cap back. My solution: paper or in a plastic bag, and hope that the shutter is not pressed out of himself again. One would be tempted to wrap the closure with scotch tape, but then so does the stone is no longer real. Maybe one has an idea for closing ...