Deutschland! Ein Freund schickt mir diese immer wieder. Was bedeuten sie? Wer sind diese Figuren?

The main characters of the „Was ist was?“ TV show for kids from the 2000s. 

The blue question mark is called Theo, the red exclamation mark is Tess and there‘s usually a third one which is a yellow full stop called Quentin. 

https://de.m.wikipedia.org/wiki/Was_ist_was_TV

I’m sure u/CostasGuatemala can explain