English: The Isolation Forest algorithm segments the data space using lines that are parallel to the standard basis, and assigns higher anomaly scores to data points that need few segmentations to be isolated. Here, the algorithm was applied to the Old Faithful dataset, which is a 2-dimensional describing the waiting time between eruptions and the duration of the eruption for the Old Faithful geyser in Yellowstone National Park, Wyoming, USA. Darker shades of red indicate higher estimated anomaly scores.