Histograms of the birth radii of stars which populate the boxy bulge at t = 3.95 Gyr, for a simulated galaxy with B/D = 0. In each panel, stars have been sorted according to their birth radius: r_ini ≤ 0.4r_bar (red histogram); 0.4r_bar ≤ r_ini ≤ 0.7r_bar (green histogram); 0.7r_bar ≤ r_ini ≤ r_bar (blue histogram); r_bar ≤ r_ini ≤ 1.3r_bar (cyan histogram); 1.3r_bar ≤ r_ini ≤ 1.6r_bar (purple histogram); 1.6r_bar ≤ r_ini ≤ 1.9r_bar (yellow histogram). Each panel in the bottom figure corresponds to an element of the grid shown in the top-right figure. For each of those elements, the contribution of stars of a given provenance in the disk has been normalized to the total number of stars which populate that element. Only stars in the bar region, that is inside the yellow rectangle shown in the top-left figure, have been included in this plot.