Introduced on day 17
ICE plot (individual conditional expectation)
The partial-dependence curve drawn separately for each row, showing heterogeneity and interactions that the averaged PDP hides.
In detail
Each line is one row's prediction as the feature varies with that row's other values fixed. Colouring lines by a candidate moderator, or centering them at the left edge, makes interactions visible (Goldstein et al., 2015).