The riddle about the Russian alphabet.

My little son is starting to speak.

He is only two years old, and only knows a few  dozen words.

I am trying to teach him alphabet at the same time.


I have cards with russian letters, and I often show them to him.

For now, he knows a few letters.

М - Мама  Mother
П - Папа    Father
В - Вова     His name
Д - Деда   Grandfather
Б - Баба    Grandmother

When we walk back home from his preschool, he always looks for these letters and he gets happy when he sees  them.

Actually, it's impossible to move him away from these symbols. He stops and starts to repeat all familiar letters again and again.

One day we were in the elevator, and he starts to tell me: Hey, there is my symbol. And grandfather's symbol, and grandmother's symbol.

I was confused, I couldn't find this symbols.

This is a picture from the elevator:

It took me a while to understand why he said that.

Can you solve this riddle?