How can I display a tux character in a shell script?

I realize this is very much of a long shot, but...

In shell scripts on Macs I can display an Apple character. Is there any way to display a Tux character (or anything else associated with Linux) on Linux systems?

The simplest solution would be if there's something in the Unicode set that symbolizes Linux, whether a Tux or something else. I haven't been able to find such a character through Googling, but maybe someone knows of one.

Another solution would be if there's some way (that I'm completely unaware of) to define characters on Linux, and display them in a terminal. (Seems impossible, but who knows? We used to do this on Commodore systems all the time!)

(I'm skipping the full backstory as to why this is useful, but the short version is that I'm looking for a way of displaying in as little space as possible in my PROMPT what kind of system I'm using, since I log into perhaps almost a hundred different servers, on different operating systems, and there are times a visual reminder would be very useful.)

If there does turn out to be a Unicode solution, I'll ask separate questions for Solaris and Windows. But this is a long shot, so no point in asking those right now.