In the [documentation for the R `compositions` package](http://www.stat.boogaart.de/compositions/UsingCompositions.pdf), and in reference to ternary diagrams, it is stated that: > However the ternary diagram can only display compositions of three > parts. In case of more parts a scatter plot matrix like matrix of > ternary diagrams is displayed which selects two components against > some sort of margin of the rest: plot(acomp(sa.lognormals5)) plot(acomp(sa.lognormals5), margin = "rcomp") plot(acomp(sa.lognormals5), margin = "Cu") In [here](http://www.stat.boogaart.de/compositions/) the author presents this (tantalizingly beautiful) plot: [![enter image description here][1]][1] ... without the code! So I've been trying to reproduce this matrix scatter plots, and understand them. For instance I am having trouble calling the multiple plots with the ellipses around points of the same variable. Here is my code and the output: library(compositions) data(SimulatedAmounts) colors = c(rgb(red=0, green=0, blue=.9, alpha=0.7), rgb(red=0, green=.9, blue=0, alpha=0.7), rgb(red=0.9, green=0, blue=0, alpha=0.7)) tt = acomp(sa.groups5) plot(tt, col = rgb(0,0,0,0), bg = colors, pch = 21, cex = .9) ellipses(mean(tt), var(tt), r = 2) [![enter image description here][2]][2] yielding only one lasso (or three lines) per ternary diagram. --- In [*Analyzing Compositional Data with R* By K. Gerald van den Boogaart, Raimon Tolosana-Delgado][3] the following plot can be found with a telling caption: [![enter image description here][4]][4] in which the radius of the lines contain 95% of the probability assuming a normal model for the composition and a known variance. The [code of this latter plot][5] likely includes the lines: r = sqrt(qchisq(p = .095, df = 2)) mm = mean(tt) vr = var(tt) ellipses(mean = mm, var = vr, r = r) and there is a clarifying comment as to the meaning of $*$: > margin = "acomp" (or nothing, the default) computes the third part as > the geometric of all components except those two from row and colum > (symbolized with "*"). --- The remaining question is: > **What are the color-coded (black, red and green) lines on the (first) plot? And, if at all possible (I understand this second part is code-specific), how can they be generated?** [1]: https://i.sstatic.net/jrtm7.png [2]: https://i.sstatic.net/eXQHS.png [3]: https://www.amazon.com/gp/search?index=books&linkCode=qs&keywords=9783642368097 [4]: https://i.sstatic.net/5UHJu.png [5]: https://books.google.com/books?id=4VhEAAAAQBAJ&pg=PA85&lpg=PA85&dq=scatterplot%20matrix%20in%20r%20pairs%20compositions&source=bl&ots=_cprO09W5I&sig=qlfAv4uwf7HyNB23PHb5PzrGS8k&hl=en&sa=X&ved=0ahUKEwjyp5avr7bTAhWE7iYKHY-uCPsQ6AEIUzAJ#v=onepage&q=scatterplot%20matrix%20in%20r%20pairs%20compositions&f=false