Sunday, November 17, 2013

Solved Blockly Maze level 10.

So I introduced Blockly on Friday to the students in Grade 6. We have four classes total to cover a topic and I thought Blockly would be the perfect introduction to the topic. It is pretty simple, has at least 3 different activities that are suitable for the students in Grade 6, and it is very visual, so you can see what happens almost right away as soon as you use your blocks of code. Finally, my preferred method of teaching the topic further was Scratch, the programming language for kids from MITs Lifelong Kindergarten group, and Blockly has enough similarities to make the transition easy.

I had the students do the Puzzle Blockly app first, which is pretty easy. Four Flags, four language, and 8 cities all have to be matched. It isn't that hard, and as long as you know some of them, process of elimination will allow you figure out the rest. Plus, when you check the answers it gives you a hint by highlighting one of your blocks that is in the incorrect spot. Overall, except for some noticeable gaps in geography knowledge (Shanghai in Germany?!?) this section went perfectly.

Matching flags, languages and cities.

The second section was Maze Blockly. Here you had to maneuver Pegman from Google Maps through a series of mazes. You could also switch him to a Panda or a SpaceSuit with a corresponding change in location, but I didn't tell anyone that. It was "the cool thing" you could find out all by yourself. The mazes start off quite easy, but there seems to be a reason for that. By the time you finish level 5 you should have more than a decent grasp of all the moves you need, the left/right turns, and the repeat. Level 6 introduces if/then statements, and from then on ramps up the difficulty fast. I'd say about 50% of the classes made it past level 8, probably a further 20% made it through level 9, but really I only had a couple of students total who completed level 10. Level 10 was hard! I had previously used Blockly, and thought I knew how to complete it, but it was obviously updated since the last time I used it and Maze 10 was much harder. What annoyed me was that once the first class left, the only ones who had any students who solved it, I couldn't remember how to solve it! It was driving me crazy all weekend, so I finally got up Sunday morning and figured out at least one possible solution for it.

Level 10 was harder because you couldn't just issue a couple of instructions and watch Pegman waltz to the end, you had to set up the blocks so he could keep moving without getting stuck in any of the dead ends that were in the maze. They do give you a hint when you start, that you should try to follow the left wall. I understood it, because I knew what that meant but my many attempts to use just left turns in the maze were fruitless. I was frustrated too because I could make Pegman check out the area in front, to the left, and to the right, and I felt that if I could just make him check out behind everything would be all good. But the tools didn't let you do that...

Then I realized what was almost as good. TWO TURNS! If Pegman just made two turns, he would be pulling a 180 degree turn, and he could face the other direction. So if I did an

If ahead-->Do--> Move forward
Else-->Turn Right
            Turn Right

That meant that every time Pegman was stuck in a dead end it would just turn all the way around. Then I could use the hint about following the left wall and stick with left turns. Eventually Pegman worked his way through the Maze and hit the end pin.

One solution to Blockly Level 10

So that was one solution. I don't even think it was the best one, because I could tell it barely worked. I might mess around with it further to find a better solution, especially as I had 3 more blocks I could have used. For now though, its all I got. Here is the direct link to my Blockly level 10 maze solution.

Oh yea, the third thing the students did after the maze. Some of them did get frustrated with Maze 9 and Maze 10, something I could hardly fault them for. So after they showed me that they had at least made a serious attempt on those two, I sent them on to Turtle Graphics. Which is very similar to the old Logo turtle. I just asked the students to try using the tool to draw the initials for the name. More than a couple were successful here, although I did have to explain to all of them the Pen-Up and Pen-Down command so they could move on to the second letter.

I asked students to draw their initials. This was big time cheating.

Overall though, I would say it went pretty well and it was a great lead in to trying out Scratch for the next couple of classes.


  1. Hi,

    they suggest to follow the left-hand-side wall, here is the program doing so :)

  2. Hi,

    here is another program taking the shortest way possible.