Today we are releasing our newest set of “Download and Print” cards for Valentine’s day. This is our seventh year, and seventh set of cards. The 2013 set had six equation-heavy cards, the 2014 set was a set of six symbol-heavy cards, and the 2015 set included love, hearts, and arrows. The 2016 set featured Pluto’s cold heart, and the perfect card for your robotic expression of love. In 2017 we featured atomic orbitals, exponential growth, and an epsilon delta declaration of love. The 2018 set featured normal force, stable equilibriums, and something about RPN calculators.

This year’s set features geometry, division by zero, batteries, a nod to quantum chromodynamics, and two very bad puns. (Sorry not sorry.)

To the extent that it is important that romance is rational, this is an extremely romantic card.

A proton or neutron is made up of three quarks, but its mass turns out to be dominated by chromodynamic binding energy, not the mass of those quarks. Corollary: By weight, humans are almost entirely binding energy.

Unlike most Valentine’s cards, which neglect the vast majority of your potential paramour, this card will let them know that you appreciate more than a tiny fraction of them.

I tried to compute my love for you but my calculator gave me an error.

Like a LiPo battery charged at the proper rate so that it does not explode.

You had better be positive before you give this card to someone.

You can download the full set here, which includes all 42 designs from all seven years (PDF, 1.8 MB).

As usual, print them out on (or otherwise affix to) card stock, personalize, and [some steps omitted] enjoy the resulting lifelong romance.