This guide is still a work in progress; I only started writing it because I was trying to figure out what all these things do and didn't find a good guide already out there!

Contraptions can be built with many different parts; some are easy to find and others... less so.

You can find these attached to the cat's 'tail'.

These are the most basic structures in your contraption; rigid sticks that attach one thing to another.

You can find these attached to the cat's 'tail'.

These are like wooden sticks, except that they pass through other contraption structures (although not the ground).

You can find these attached to the cat's back.

These turn in the direction indicated by the arrow. Attach things to the points on the sides (like an axel) to all the powered wheel to drive a contraption forward. Attach things to the points on the face of the wheel to spin those things around at high speed!

You can find these by pulling them out of your left ear.

These wheels turn freely and are not powered. They can be a great way to add weight to a contraption or they can make a nice guide for something else to smoothly roll over.

Glue can be found on the cat's belly, or from your right ear.

By default, joints are flexible. That is to say that where two objects, such as two sticks, connect to each other, they can rotate freely. This free rotation might make your whole contraption literally collapse under its own weight! You can stick glue on the joint to fix those objects in place; suddenly your tower doesn't need so much bracing to hold itself up any more!

Pins are found on the cat's head.

How do you delete a stick or a wheel or whatever? You don't; instead, you pop it with a pin! Those lollipop looking things sticking out of the cats head are actually pins; just grab one and you can use it to pop whatever objects you want. Just be careful to only pop the objects that you want to pop! When I'm done with a pin, I just grab another to pop that pin, so that I don't have to worry.... just kidding, I really throw it off the edge of the world.

This is on the cat's collar.

I don't know what this does, but it can be fun! The "bell" on the cat's collar is a bouncy ball, which has physics even when you're in build mode. You can throw it around and can even attach it to sticks. From some very basic testing, it doesn't appear to have weight, so I'm not sure how it could be used in a machine.