The printed artwork reads I WEAR THIS SHIRT PERIODICALLY, and beneath or beside that sentence sit four periodic-table-style tiles: 53 I, 74 W, 22 Ti, 16 S. The tile symbols are I W Ti S. They are not a literal spelling of the sentence above them. That gap is the whole design, and it is worth reading carefully rather than laughing past.
Here is the obvious layer first. The sentence uses periodically in its ordinary adverbial sense: now and then, from time to time. The tiles use periodic in its chemistry sense: the periodic table, the arrangement of elements by atomic number. The shirt is a pun built on one word carrying two jobs. That much is visible on the garment and does not require a citation.
The less obvious layer is the tile sequence itself. A viewer who knows the table will read the tiles as element symbols and atomic numbers: iodine at 53, tungsten at 74, titanium at 22, sulfur at 16. A viewer who does not know the table will try to read the tiles as letters and fail, because I W Ti S does not spell periodically or anything else in English. The design depends on that failure being funny rather than frustrating. It works because the tiles are close enough to letters to invite a reading and far enough from letters to refuse one.
That refusal is the part I keep coming back to. The shirt is not a diagram of the periodic table. It is not a chemistry lesson. It is a sentence that has been routed through the visual grammar of the table and come out the other side as a joke about how often the wearer puts the shirt on. The tiles are decoration that happens to be load-bearing. Remove them and the sentence is a flat statement. Keep them and the sentence becomes a small puzzle with a punchline.
There is a useful distinction here between a slogan and a usable promise. A slogan asserts something and stops. A usable promise tells you what will happen and when. I wear this shirt periodically is closer to the second kind, because periodically is a frequency claim, not a quality claim. It does not say the shirt is good, comfortable, or meaningful. It says the shirt appears on a schedule the wearer has not specified. The element tiles then undercut even that modest claim by making the word periodically do double duty. The result is a shirt that promises almost nothing and delivers a small piece of wordplay instead. For a certain kind of technical reader, that is a more honest contract than most apparel copy.
I would not read the tile arrangement as evidence of anything beyond the design. It does not demonstrate a chemistry result, a software behavior, or an engineering outcome. It is a visual joke, and the joke is legible from the artwork alone. The atomic numbers and symbols are consistent with the standard periodic table, which is what makes the tiles readable as tiles rather than as arbitrary glyphs. But the shirt is not making a scientific claim. It is making a language claim, and the claim is that one word can be pulled in two directions at once without breaking.
If you want the object itself, the listing is here: I Wear This Shirt Periodically Funny Chemistry Science Pun. The design is the one described above: the sentence, the four tiles, the mismatch between them. That mismatch is the reason to look at it twice.
Editorial note: This publication and Quirky Cotton Collective share an owner.