<a href="https://possiblyfunny.tumblr.com/" style="text-decoration:underline;">possiblyfunny</a>:
<p><i>Oooh~?</i> A lockbox with a passcode?</p><p>Is there any way to check how long the passcode is? Just to see how many numbers we need. <i>I’ve got a couple ideas…</i></p>
It doesn’t look like a typical numberpad- none of the buttons are labled, and there’s too many to correspond to a typical 1-9 layout.
You poke at it curiously, pressing a single button- with a click, it lights up. Maybe it wants a pattern of some kind.