Attempts to fool 4o with my middleschool cryptography secret code with my best friend have failed miserably and instantly, first try

In middle school my best friend and I came up with a secret code We would only write the top part of the letter, but leaving enough you could figure it out. I tested 4o with just the very top of the letters, an extreme version of our secret code, just to see what kind of skill it had with this and it got it right immediately. I don’t know what this means but we won’t be able to fool Ai with something that has stumped every adult I’ve asked