diff --git a/d03/README.md b/d03/README.md
index bb6b344..b9500ab 100644
--- a/d03/README.md
+++ b/d03/README.md
@@ -11,4 +11,9 @@
 gs -sDEVICE=pdfwrite -sOutputFile=out.pdf -dNOSAFER -- day3.ps <input file path>
 ```
 
-## Notes
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+(this code uses `.shellarguments` to read the name of the input file from the CLI arguments,
+which I believe is a GhostScript-only thing, so this probably won't work on other PostScript
+interpreters without some modification.)
+
+## Notes
+I think this one was better than day 1 again. It took me a while due to never having used PostScript before, but stack-based languages are always fun.
\ No newline at end of file