Symbol "Dangerous bend"

#1

I would like to type the LaTeX symbol “dangerous bend” (\dbend or equivalents) in TeXmacs, or “!” in a “Big triangle up”.
Thanks for help !
R. A.

#2

I looked it up and I have one answer where you need to program.
The dangerous bend is U+2621 (press Ctrl+Q and then type #2621 within the brackets), and I think that you need to build up the rest with a character combination.

Here is an example: Relational Algebra join/latex \bowtie character

Then assign to a macro or to a keyboard shortcut.