BioShock Infinite’s crossbow plays into the game at a few points, particularly in part two, Burial at Sea. Cosplayer Sonia, a.k.a Redditor ElizabethAck, made the weapon wielded by Elizabeth and put together a tutorial documenting the build in English and Italian. After getting reference pictures, she drew the weapon and made the body of the crossbow from plywood (which you can see below). She explained:
The central body of the crossbow is made out of plywood. This part was planned together with my boyfriend, he actually drew the CAD and used a laser cutter to make the pieces (only the wood is laser cutted, all the other parts are cutted by hand). We made 13 layers (1 layer is 4 mm thick), with different shapes to get a approximately the crossbow shape. The pieces were glued together. I sanded it down and plastered it several time, until the rounded part were properly shaped. At the end I applied the details, made out of forex (and a piece of pencil actually).
Read more of the tutorial and view additional photos at Tumblr.