Batch 3 - Class 203 - Mad Vet Puzzles

• Complete the state diagram for the wolf-goat-cabbage problem, with actions on the following chart

• Think of tic-tac-toe as a state machine. Draw the states and transitions
• Program one of the finite stage machines above (or one of your choice) using App Inventor

• A Mad Veterinarian has created three animal transmogrifying machines. Place a cat in the input bin of the first machine, press the button, and .... whirrr .... bing! Open the output bins to find four dogs and one mouse. The second machine can convert a dog into three cats and three mice, and the third machine can convert a mouse into a cat and a dog. Each machine can also operate in reverse (e.g., if you’ve got two dogs and five mice, you can convert them into a cat.) This Mad Vet has one cat.
• Can he convert it into seven mice?
• Answer: Yes (1, 2, -3, -3, -3)
• Can he convert it into a pack of dogs, with no cats or mice left over?
• Answer: No (Number of Cats plus Mice is an even/odd invariant)
• Another Mad Vet has created a two animal transmogrifying machine. Machine #1 turns one cat into one dog and one cat. Machine #2 turns one dog into two cats. This Mad Vet has one cat.
• Can he convert it into 4 cats and a dog?
• Answer: Yes (1,1,2)
• Can he convert it into 2 cats and 2 dogs?
• Answer: No (Number of cats remains even or odd, whatever it started with)
• Ask the class to think about what can be done, and what can't from a starting point?
• Ensure that the kids can think of this as a state diagram
• Can you see the pattern to say what is possible and what isn't?
• Discuss a representation as a graph on a 2D plane (along X/Y axes) - are they able to see the patterns now?

• Apply the two dimensional representation to the first problem above by using C+M as X-axis
• How would you program a mad vet setup on Appinventor?
• What if Machine #1 above turns a cat into 2 dogs and a cat? What is possible and what isn't?
• Ask kids to think about the state diagram view, as well as a graph view

• (Moscow - 58) Stopped Clock - My clock stopped. I went to my friend's place, saw the time and waited for some time, and came back and set my clock right. How did I do it without knowing the time it took me to travel from my friends house back to mine