Seventies' children's animation (UK) involved eponymous characters: Mary, a girl, Mungo, a dog, and Midge, a mouse. It was all probably a reaction to the rather 'pastoral' qualities of children's shows as this one was all very much 'urban'. They lived in a tower block for a start. It also seemed rather anti-stereotypes too. Mary's 'family' group was certainly a little quirky.
Whenever they went up or down in the lift, and this is the bit that everyone remembers, the mouse would sit on the dog's head, and all three of them would watch the lit-up numbers as they rose and fell. Urban poetry really.
In one episode. Midge, always the inquisitive one, got sealed in an envelope and got posted... why Mary didn`t notice a strage mouse shaped bump in her envelope we shall never know. He then got sent through the various stages of how a letter reaches its destination. Thankfully it was a card sent to Mary`s Aunt who brought back Midge safe and sound... all beautifully narrated by Richard Baker.
In my head, Mary looks like Crystal-Tips, so I wonder if one inspired the other. | 
