Resin would be very interesting. The tube design seals them everywhere below the top layer. And the two ends of the tube tops are always at the same Z. You cou

Resin would be very interesting. The tube design seals them everywhere below the top layer. And the two ends of the tube tops are always at the same Z. You could technically inject anything liquid enough into the tubes. Grout, resin, glue, silicone.