Creativity vs. Vandalism

It seems like every time I turn around I am finding my children's names inscribed in the house, courtesy of my five year old. (So far Lila has only mastered the letter L, and Jake would probably be writing haiku or slam poetry instead of just names.) Not on walls (so far) but on toys, books, tables and chairs, and the frame of the easel! That one just kills me. There is a chalkboard side and dry erase side and an enormously large roll of paper just for the kids to draw on! Why do you have to use marker on the wood frame of the easel?! I don't want to stifle the artistic nature Evie seems to be developing, but I am a little afraid I have a budding graffiti artist on my hands. I am this close to putting all art supplies under lock and key. Which could be a little awkward as that means fully half of Evie's Christmas presents will be taken away as soon as she opens them...