It appeared an impossible task, given the complicated technology: Juanita Brooks had to explain to a jury why her client’s peritoneal dialysis cycler — a device for treating kidney disease — did not infringe on a patent held by Baxter Healthcare Corp.
To do so, she needed to prove that a piston within the device would not work like a key corresponding feature of the rival patent. So she drew a picture. With an actual piston in hand, she traced its curvature, producing a half-circle. She also drew a straight line to represent the part to which the piston attaches. Under Baxter’s patent, the two lines had to be the same.
