Come on, Ed! One can't even compare the taste of an Extra Vigin Olive Oil to that of Mineral Oil. I'm sure he want's his child to grow up with a taste for the finer things in life, such as Italian food!

I'll grant you that mineral oil won't get rancid, but if the child puts the blocks in her mouth constantly, then reapplication of olive oil once a month or so should be enough to keep rancidity at bay while maintaining a desired level of taste sensation... Hmmmm,

two colored blocks: make half of them out of olive wood, with olive oil finish, and the other half out of walnut, with walnut oil finish! Yes! Contrasting colors and flavors as well...
Claude