My 3.5 year old daughter also has these kind of tantrums if she cannot figure something out immediately or if it does not live up to her vision. The other day she pulled one of her fits and I told her that she was done with her pencil for now and could choose something else to draw with. Changing to another medium (markers in this case) seemed to clear her mind and help her start anew.

I like the dot to dots idea!