About plotting, I added labels, including the gesture number, cognitive load level and recognise result, on each gesture to show the attribute clearer.
Also, I reviewed two papers discussing the gesture features. They are all about the geometrical features of a gesture, ranging from simple ones like length, bounding box, and some complicated ones curvature and sharpness. In the papers, these features were used in handwritten recognition or input mode detection. They gave me some ideas about the feature selection, and I will search for more papers in the topic "online input recognition" (--> general features) and "handwriting verification" (--> subjective features). For my study, the features should be sensitive to the cognitive load and easy to test. I think the sharpness and other features related to angles between certain points might be potential good features, and I will summarise and test them in the next stage.