The work "Memorial stones" re­ve­als the ar­tist's apo­ca­lyp­tic vi­si­ons of the fu­ture and has its star­ting point in his preoc­cupa­ti­on with his­to­ri­cal en­viron­men­tal ca­ta­stro­phes such as the Thu­rin­gi­an Flood of 1613, of which the­re are va­rious his­to­ri­cal re­cords such as flood mar­kings or me­mo­ri­al sto­nes. Ba­sed on this over 400-ye­ar-old me­mo­ri­al sto­ne, which is in the Wei­mar Ci­ty Mu­se­um, the ar­tist de­ve­l­o­ped his own vi­si­ons far in­to the fu­ture and put them on sto­ne ta­blets.