This program graphs the convolution of distributions. To plot the 6-fold distribution of a distribution input the distribution into the first column and input 6 in the box labeled "No." under the first column and click on "Go."

To convolute two different distributions input the distributions into the two columns and put 1 into the two boxe under these columns and click on "Go." Putting 2 into each of these boxes will convolute the convolution of each distribution.

The source.