Knex Think-a-dot!

Introduction: Knex Think-a-dot!

About: I love knex, neocube and hammerfest (

Here I present you my take in building a k'nex version of the amazing toy think-a-dot. It has 8 'windows', through which we can see either blue or yellow (blue and orange in my build) A ball is thrown in one of the three holes, the flip flops are turned... and voilá! We've got ourselves a fun little game.

I should say that I'm not the first one to recreate thi toy in knex; it was first done by Mike Gleen. You can see it here, along with the original game's leaflet which will guide you on using it. However, I found his build rather big and impractical for the space I have avaliable; on the other hand, his contraption uses common k'nex balls instead of the metallic 'marble' I use. Also, mine does sometimes get stuck.

If anything isn't completely clear or my english is incorrect don't doubt to make a comment and I'll fix whatever's wrong. Also, sorry for the blurriness of the photos :(

Step 1: Step 1: Piece Count

Coming soon! Seriously.

Step 2: Step 2: Building the Modules

This is probably the most boring part. You'll have to build 8 times the same module, which is basically a flip flop. Just follow the pictures.

Step 3: Step 3: Modifying Modules

So you now have 8 basic modules. Now each of them has to be transformed slightly. In the end you should have 2 'bottom sides' modules, 3 'top' modules and 3 'heart' modules

Step 4: Step 4: Building the Base

So now you'll build the base of the game, including the tracks for getting the ball out from one side or the other.

Step 5: Step 5: Going Up!

Step 6: Step 6: the End!

I forgot to take pictures for this one, but it's pretty simple: just connect the 3 'top' modules to the top of the building, same as in previous steps you did with the heart modules. Now, take your ball or marble or whatever and throw it repeatedly between the yellow bars on top, several times for each flip flop, and check everything is working. If an error persist, then try to find and share a solution :)

When you're done with the testing, just add and adjust some pieces of cardboard which are half blue, half yellow (or whatever colours you fancy). Then, add a big cardboard with holes in it, so one of the colours is seen through each window but it changes when the flip-flop moves. Done!

Step 7:

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    8 years ago on Introduction

    Thanks for sharing! I hope you complete those missing steps! Do you have a video of the game in action?