Minifigs
The LEGO Group is already the world's largest tire manufacturer.
The LEGO Group is already the world's largest tire manufacturer.
Lego minifigures (often abbreviated as minifigs) are tiny plastic people designed by the Danish toy manufacturer Lego as part of their construction toy sets. Since 1978, over four billion minifigures have been sold, so they still have a long way to go before they surpass the human population (which is around 8 billion). The figures resemble simplified humans, often with a yellow skin color and featuring interchangeable body parts, such as legs, torsos, heads, hair, and hats.
The graph depicted in the comic extrapolates the total number of minifigures and compares it to the growth of the world population, which reached 7 billion in March 2012. By the extrapolations of the comic, Lego minifigures will outnumber the human population by 2019. The extrapolation of statistical data has appeared in various xkcd comics, e.g. in 605: Extrapolating, 1007: Sustainable, and 1204: Detail. However, unlike the other extrapolated scenarios, the prognosis of this comic seems quite likely.
Since Lego is designed to resemble nature and civilization on a miniaturized scale, some sets also contain Lego cars as vehicles for the minifigures. With over 381 million Lego tires produced for these miniature cars, Lego is already the world's largest manufacturer of tires. This fact is addressed in the title text.
Lego (as of mid-October 2013) calculates they have made 7 billion+ figures. Earlier in 2013, they believed they would surpass the human count in 2014, but revised their numbers on the day this comic was released to what this chart says. (In 2019, there were 7.7 billion people and 7.9 billion minifigs, so this was true.)
Extrapolation and interpolation, often absurd, are recurrent topics on xkcd.