Haha, I forgot about IDL. My very first coding project as an undergrad was in IDL, until one day a new grad student showed up to the lab and said, &quot;WTF? Do this in python.&quot;<p>When looking at plots in papers, there are always little giveaways for what program it was made in. Plot has horizontal gridlines, but no vertical gridlines: Excel. Plot is typeset with Arial, size 4: Matlab. Plot looks like it was sent through a fax a few times: IDL.