How do I turn this sensor data into a conditional statement to categorize the data as one shape or another?

So the graph below shows data collected from a real time simulation application called CoppeliaSim, I want to know how to go about categorizing is so that the data can be understood as a respective shape, so that I can reject the cylinders in the application. All of the data that forms a U represents a cylinder, while the other three represent cubes at different angles.