These piers guide boats under bridges. They come is mirror image sets of two and are modular. There are three different variations plus one to link the piers sets on each side of the bridge.
These were originally available in WSF and I have some of my own, but shapeways changed their mind and now won’t print them because they are supposedly too detailed for WSF.
5.232 w x
1.022 d x
2.06 w x
0.402 d x