Oh sorry, I’m afraid you don’t understand the poblem I deal with. This figure is one varable of my model which contains a lot of subjects’ data. Each subject(n_subj) has this varable(theta) at each trial(n_trial). n_sample is 1000. That is, the theta size is “n_subjn_trialn_sample”(I use trace_to_dataframe to know the column index of it, which likes “theta__isubject_itrial”, which has 1000 rows because it has 1000 samples), using plot_trace, it will return a long figure contains these subjects’ results which likes what I show above (each row is one subject’s theta trace and there shows 20 subjects’ theta trace). I want to plot the figure for each subject’s trace, that is, plot 20 figures for 20 subjects’ theta.