Lol, when you said you were putting one together for a 4-year old i was thinking "oh that is a terrible present for a young child!" but then you clarified. :) A lunch box has enough power to seriously injure someone, i know this because we tried to hurt one another with our cars.
The more i think about this thing the more i want to give it another go.
So funny that you found me while you were putting together a truck by the same company :)
I must say even though it wasn't as big as a Lunch Box it was still a very inapropriate present for a 4 year old!