U-BMD font for laplace's transform

.gitignore

@@ -22,7 +22,6 @@ nnn
 xarchiver
 monero-project
 GIMP
-README.md
 caja
 cinnamon
 discord

groff/README.md

@@ -0,0 +1,16 @@
+# sboxes
+
+Keep in mind, the macro utils.tmac sources sboxes.tmac, but
+that macro is exclusive to groff v1.23.0, which is not
+present on Debian 12. Compiling it from source is really
+easy though, thanks to GNU's coding standards.
+
+# Custom fonts & glyphs
+
+In order to install the U-BMD font,
+required for U+2112 '_Laplace transform_' glyph, just copy the
+provided file to groff's site-font directory, like so:
+
+```shell
+cp ~/.config/groff/site-font/U-BMD /usr/share/groff/site-font/devpdf/U-BMD
+```

groff/math.tmac

@@ -44,8 +44,8 @@ define arccoth 'roman "arccoth"'
 define arccsch 'roman "arccsch"'
 .EN
 .
-.\" Laplace transform/Lagrangian in NU font
-.char \[letterlikeL] \f[NU]\[u2112]
+.\" Laplace transform/Lagrangian in U-BMD font
+.char \[letterlikeL] \f[U-BMD]\[u2112]
 .EQ
 define lap '\[letterlikeL]'
 define lag '\[letterlikeL]'