I had an 'old' moment

Occasionally I forget that I'm getting older, particularly at work. Until two weeks ago. I was trying to explain to a new co-worker how the special kind of triplicate form worked, and I mentioned that it looked kinda like a ditto used to (purplish ink from the carbon). You know, those purple text pages we used to have in elementary school rather than the copies we have now? He definitely looked at me and said 'What's a ditto?'. to make it worse, when I explained he said (I kid you not) 'I think my mom told me about those'. So, not only did he not remember, he lumped me in a category with him mom. Good grief. Please tell me someone out there remembers those ditto copies from grade school???