I use my diary every day and someone has noticed this! Tiny has observed me writing in it and now she loves flicking through pages and scribbling all over it. I don't mind as I'll enjoy one day looking back over my 2018 diary and seeing all her lovely marks. I think she's imitating what she observes me doing but again she engages most enthusiastically with 'real life' activities. For instance she loves pushing her own push chair rather than the dolls one we bought her; she adores ploughing through my wallet and now would prefer scribbling in my diary much more than using the paper I give her.
She then moved on to her knee which became a mark-making sensory experience!