How many channels encode data in this chart?

What channel(s) encode the miles per gallon (of a single data point - a car)?

How many different types of marks are used in this chart?

How were all these marks overlayed on top of one another? (altair code)

How many channels are encoded in the rule (the connections) mark of this chart?

What channel is used for denoting literary theme?

How many channels are used in this data visualization?

What does the y axis (different heights of the cone) represent?

What does the angle of the cone represent?