Decision Trees (the upside-down trees)

Taking SpongeBob SquarePants' mood as an example, based on historical data, there are two factors that affect whether he is happy or upset. So, if the whole mood table of Mr. SquarePants is visualized into a scatter plot, it will look as the following: Decision trees are used in classification problems to find a line(s) that separates the data as perfectly as possible. The separation process is done by measuring the homogeneity or similarity of the data. Attempting to separate data, a vertical line is drawn to separate happy SpongeBob from upset SpongeBob, taking into consideration one feature only -which is the number of jellyfish that were hunted. A vertical line at the number 10 on the x-axis can work as a separator, so if the number of jellyfish hunted is less than 10 SpongeBob is upset otherwise, he is happy.