Amy Cohen points us to this fun article by Noeska Smit. Here’s the description of the above-pictured fuzzy heart model:

The last sample I [Smit] knit is a simplified 3D anatomical heart (see Figure 4) in a wool-nylon blend (Garnstudio DROPS Big Fabel), based on a free pattern by Kristin Ledgett. She has created a knitting pattern that is knit in a combination of in the round and flat knitting techniques. This allows the entire heart to be knit in one piece, with only minimal sewing where the vessels split, visible in Figure 4b. The heart is filled with soft stuffing material while it is knit.

This sample is a proof of concept for how hand knitting can be used to represent complex 3D structures. While this sample is not anatomically correct, it demonstrates how the softness and flexibility of the stuffed knit allow for complex 3D shapes to be created using only basic knitting techniques. As the vessels are not sewn down, this particular model can be ‘unknotted’ and put back together freely. This sample only requires basic knitting knowledge on how to cast on, knit, purl, increase and decrease stitches, and bind off. The combination of the soft stuffing with the fuzzy knitted material gives an almost cartoon-like impression, in stark contrast to how disembodied human hearts typically appear in the real world. In a way, this makes a medical concept where a realistic representation can elicit a strong negative response more approachable. Perhaps it is similar to how surgical images can be made more palatable by using color manipulation and stylization.

What can I say? I love this sort of thing.

P.S. More here: “‘Knitting Is Coding’ and Yarn Is Programmable in This Physics Lab”