diff --git a/GPT3/README.md b/GPT3.5/README.md
similarity index 87%
rename from GPT3/README.md
rename to GPT3.5/README.md
index d44e9e6..9c132eb 100644
--- a/GPT3/README.md
+++ b/GPT3.5/README.md
@@ -1,4 +1,4 @@
-## gpt3
+## GPT3 or 4, who knows?
 
 <br>
 
@@ -18,3 +18,4 @@
 * [calculate time complexity](https://platform.openai.com/playground/p/default-time-complexity?model=text-davinci-003)
 * [text to programmatic command](https://platform.openai.com/playground/p/default-text-to-command?model=text-davinci-003)
 * [travel hero, by dabit](https://gpt-travel-advisor.vercel.app/)
+* [vitalik and his fun time travel experiment](https://vitalik.ca/general/2023/04/14/traveltime.html)