Some time ago, I needed urgently a redoubt for tomorrow's game... I needed a redoubt with angled front breastworks for 1/72 scale, to house 3 batteries (bases of 4cmx8cm) and at the same time each side to have at least 10cm frontage so as to be able to substitute on or more batteries with infantry base(s) of 8 cm frontage.
The breastworks were made from three progressively smaller steps of cork, 0.5cm thick. To make the surface smoother, I filled it with plasteline (!) smeared with PVA glue. This lets the surface quite flexible as you work, but it hardens after about one day. After opening gunports, I dressed the outer surface with grass paper for train modelling. I used thin balsa wood for the supporting planking of the inner walls. With a biro I designed the planks (you can see still the traces of the biro marks, as I was in extreme hurry ). I glued in position balsa wood for the floor planking where the cannons would rest, etching it slightly with an x-acto knife. Then I poured some earth and sand on the inner surface. After letting the whole thing dry for a while, I did some drybrushing, adding some bits and odds (a bucket, a broken wheel) here and there. I sprinkled some static grass in some places, as well as on gaps left by the grass paper at the outer surface. The whole procedure took me less than four hours.