Learning Java Collections and Interfaces with Frogs, Sheep and Owls

A couple of days ago a funny drawing from Twitter caught my eye. I thought it would make a good exercise for kids learning Java. Here it is:

For some lunch time #fun: are you able to #solve this #mathquiz? https://t.co/cZWVc26P2b #justforfun #math pic.twitter.com/YWmVM9yezd

— sqlbythebook (@sqlbythebook) November 24, 2015

I quickly drafted a model and saved it at GitHub:

I had thought the exercise would be easy, but when I started to sketch a program to solve the puzzle I realized that was not the case. Knowledge of Java collections and interfaces seemed to be neccessary. Moreover, teaching the computer how to determine X, knowing that X*X*X = 27, raised unexpected issues:

Trying to figure out why Math.pow(27,1/3) returns 1 https://t.co/JA1cnnshQp #java

— C. Fierbinteanu (@inafierbinteanu) November 26, 2015

What do you think? Are these quizzes helpful in teaching kids programming?

I am looking forward to your opinions in the comments below or at Moodle Cloud.