Checkbox
Checkbox
[A small box is in the middle of a large white frame. The box can have a check-mark, but it is alternating between being checked or unchecked. At the bottom right there is a muted speaker (which can be unmuted). If the user press the checkbox gray dots or lines will appear below depending on the length of the press. These will move from right to left and then disappear.]

This was the 11th April fools' comic released by Randall . The previous fools comic was 2288: Collector's Edition , which was delayed two days and released on Friday April 3, 2020. The next became 2601: Instructions released on Friday April 1, 2022 (a regular release day).
The comic looks similar to a loading screen. The actual comic (this “loading screen”) consists of an animated gif of a checkbox (hence the name).
The frame is replaced with an interactive panel. In the center is a check box, which clears itself immediately when checked. In the bottom right is a mute button, which begins muted. By unmuting, and changing it to a loudspeaker, sounds are played when the check box is checked. This was the first comic with audio on xkcd. But the very similar Fool's comic from the next year, 2601: Instructions , used audio as the main part of the joke. This comic and also has a mute button (but here the sound was on when the mute button is shown, seems like an error). This comic is also very similar to this one, as it only has one thing in the center, but not a check box, but a radio button .
Under the checkbox is a scrolling visual representation of the timing and duration of clicks in the check box, which also produce matching beeping sounds when unmuted. The representation consists of a dot for a short press, or a bar for a longer press. All long presses are represented by a bar of a pre-determined length; in other words, a longer press does not result in a longer bar.
By varying between brief and long presses, and brief and long intervals between presses, it is possible to enter characters in Morse Code.
The check box then begins operating by itself, producing sounds which can be decoded as Morse Code. These responses are also printed in the browser's JavaScript console in both plain text and a textual representation of Morse code. If left without any initial input for 30 seconds it would send the message CQ (meaning "Seek You").
The title text hints at the use of Morse Code in the comic; interpreting the "check" as a Morse Code dot and the "chhecck" (a long check) as a Morse Code dash gives ...---..., which is the Morse Code for "SOS", the international distress signal. Incidentally, inputting the SOS signal gives "YOU TOO?".
For the majority of inputs, the check box responds with a random selection from the following list:
Some keywords, however, have special responses .
This comic has a unique header text , see the details here . The header is:
"This comic was put together by Max Goodhart, Patrick, Amber, Benjamin Staffin, Kevin Cotrone, and Michael Leuchtenburg."
Read Max's blog post on development of the comic.
[. represents a short signal, - represents a long signal, and / represents pauses between words. Sojourner is a Mars rover which has been referenced by Randall in the past and is the entity operating the morse code device.]
See also QRS and QRQ.
An explanation of Q codes can be found here .
Steps to complete (directions can be abbreviated as their first letter):
After successfully repairing and rebooting Sojourner, a comic is opened which depicts it seeking out and finding its friends, Spirit, Opportunity, Curiosity, Perseverance, and Ingenuity. Curiosity and Perseverance are locked in a swordfight, and either Spirit or Opportunity is carried off by Ingenuity while the other speeds off a small mound of dirt. Ingenuity carrying a rover is a reference to the previous comic.
The page's JavaScript creates a global object morse with encode and decode methods.  From the developer console, it is possible to write morse.encode("A PHRASE") , which will print the Morse code corresponding to the text provided, or morse.decode("... --- ...") which will translate the Morse code to text.
BeepComic.hurryUp() to get the reply immediately in the console. BeepComic.send(...) to send directly to SOJOURNER.
[A small box is in the middle of a large white frame. The box can have a check-mark, but it is alternating between being checked or unchecked. At the bottom right there is a muted speaker (which can be unmuted). If the user press the checkbox gray dots or lines will appear below depending on the length of the press. These will move from right to left and then disappear.]
