Add visual note

README.md

@@ -6,6 +6,9 @@ implementation, to be found in the interpreter files. This could also be used as
 a drop-in replacement for the compiler, by changing the appropriate line in
 `main.cpp`.
 
+> [!Note]
+> Running `curly` without arguments, it will show the solution to the online puzzle. When run with file arguments, it will try to parse those files as Krul sources and run them.
+
 ## Building
 
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