Here are all the modular trench sections I have completed so far.
For those who are interested in this kind of stuff, here's how they are made:
Materials: cheap plasticine, the one used by school kids; 2mm plasticard; balsa wood; other various bits of card for the duckboards. One box of 200g plasticine is good for one section. The plasticard pieces are usually 12x20cm ones, I think the gun emplacement is 18x20 or so, and the connecting piece is 8,5x15. The rear side of the trench is 3cm wide, then a 3,5cm wide space, then a 5,5cm frontage. The front has a more gentle slope so attackers could climb it more easily and it blends more into the environment.
The trench itself is not very deep. You'd need a much broader glacis if you made it man-deep, closer to 20, 25, 30mm. This one is just 15mm tall at the front, so about waist high for a standing figure on a ~2mm thick base. You can move standing figures further back from the glacis and it would still have the visual effect required, this is a thing I learned from one of Lindybeige's videos. This can be used for other types of emplacement as well.
I use my greasy fingers and a ruler to shape the plasticine. After this is done, I just splash on a huge amount of PVA and sprinkle sand on it. Make sure to wash your hands after both of these steps.
Let the stuff dry for one or two hours before adding the running boards, stakes and whatnot. Beware that the plasticine is not very heat resistant and it may become too soft if you put it on a radiator for too long. The PVA and sand will dry to a hard surface and will protect the plasticine, so this shouldn't be a huge problem.
Wait for another 3-4 hours before undercoating with cheap brown acrylic paint. As a rule of thumb, don't use professional (and expensive) paints when covering large surfaces. Let the paint dry, apply brighter brown patches liberally, then drybrush with Buff or Iraqi Sand. Add some static grass, debris from previous battles etc.
The bunker closing down the second trench is just 6mm balsa wood, two or three riflemen or an MG can fit in it.
Most of the pieces can be arranged in a different fashion, even two opposing trench lines can be placed. With a few extensions, this will be a really fun feature of coming battles.
