I remember when DD was at this stage, I tended to amuse her with food. I got an old jelly mold the small ones and use to layer the colours .Putting mash potatoes as a layer then maybe some pumpkin mash and then some brocali mashed. She was also partial to gravy so that on the side use to get some vitamins into her.
Good luck, I hope it doesnt last for too long
B