Damon writes, “This distribution of ‘isotopic peaks’ on my calf is what a peptide of mass 2,005 Daltons looks like in a high-resolution mass spectrometer. That peak distribution is due to the relative abundance of the different isotopes of the elements that make up peptides, particularly carbon. 2005 is the year I got married and also the year I gave the corporate world the boot in favor of science. I wonder if there are any more proteomics tattoos out there….”