diff --git a/init.org b/init.org
index 9e3e78d..270b54e 100644
--- a/init.org
+++ b/init.org
@@ -87,12 +87,29 @@ Emacs variables are dynamically scoped. That's unusual for most languages, so di
 
 * Default settings
 #+BEGIN_SRC emacs-lisp
-(setq *home_desktop* (string-equal (system-name) "marc")
-      ,*home_laptop* (string-equal (system-name) "laptop")
-      ,*work_local* (string-equal (system-name) "PMPCNEU08")
-      ,*work_remote* (string-equal (system-name) "PMTS01")
-      ,*linux* (string-equal system-type 'gnu/linux)
-      ,*windows* (string-equal system-type 'windows-nt))
+(defconst *linux*
+  (string-equal system-type 'gnu/linux)
+  "Is the system running Linux?")
+
+(defconst *windows*
+  (string-equal system-type 'windows-nt)
+  "Is the system running Windows?")
+
+(defconst *home_desktop*
+  (string-equal (system-name) "marc")
+  "Is emacs running on my desktop?")
+
+(defconst *home_laptop*
+  (string-equal (system-name) "laptop")
+  "Is emacs running on my laptop?")
+
+(defconst *work_local*
+  (string-equal (system-name) "PMPCNEU08")
+  "Is emacs running at work on the local system?")
+
+(defconst *work_remote*
+  (string-equal (system-name) "PMTS01")
+  "Is emacs running at work on the remote system?")
 #+END_SRC
 
 #+BEGIN_SRC emacs-lisp