Dear list I have a matrix such as the following: 1 0,5 1 0.7 1 0.5 2 1 3 0 4 0.2 I'd like to plot the histogram of the first column (this is very easy) and then for each bin of the obtained histogram to plot another histogram on the z-axis of the frequencies of the second column for the values belonging to the specific bin. In other words i have a matrix with 2 column and i'd like to find a way to represent on a 3 axes plot the frequencies of teh first column and for each obtained bar the frequencies of the second column Someone could suggest to me which package or kind of representation could be the best to achieve my goal? thank you very much Guido -- Guido Leoni National Research Institute on Food and Nutrition (I.N.R.A.N.) via Ardeatina 546 00178 Rome Italy tel + 39 06 51 49 41 (operator) + 39 06 51 49 4498 (direct) [[alternative HTML version deleted]]