First, get a good, long look at the shape of the crank. How is the central axle shaped? Are the little protrusions around the edges of the crank triangular or square?
Next, look at where those funny shapes stick out on the crank.
Starting to make sense?
While you need to pay attention to the actual features of the crank and slot, you also need to remember that the shape of the slot is a mirror image of the crank.
That's right, you have to stare at the crank straight on and then look for the slot that mirrors it.
The central axle of the crank has five sides. There are three shapes attached to the main axle, one triangle and two squares.
One of the small squares sits right on top of one of the axle's five corners, while the other two shapes sit flush on two sides of the axle.
All right, now you have everything you need. Don't forget that you need to flip the crank's shape when searching for the slot!
Solution
Incorrect
Too bad!
Take a careful look at the picture. The shape of the slot will be the reverse of the crank.