A single lentil or pea is commonly used to represent a ribosome in a matchbox model of RNA.
A ribosome is a small, dense granular particle comprising usually three or four ribosomal RNA molecules and more than 50 protein molecules, interconnected to form the site of protein synthesis.
Ribosomes occur in both prokaryotic and eukaryotic cells. A ribosome can be thought of as a giant enzyme that builds proteins from a set of genetic instructions. It is the cellular structure responsible for decoding your DNA.