This is a knex model of a dog that I just thought of in my head.

Step 1: Body Parts

This doesn't need a lot of parts but it includes

Pieces:
4 yellow pieces
6 green pieces

Connectors :
6 white connectors
2 mini green connectors
4 blue connectors

Step 2: Connecting the Body Parts Together

Follow the step as well as comparing your design in the pic.

Connect 4 white connectors to 4 green pieces

Then connect the other 2 green pieces with 2 mini green connectors

Lastly, use your 2 blue connectors at the end of the exoskeleton of the dog and use your 4 yellow pieces to hold together your 2 white connectoris and your head to give the dog a backbone.

Step 3: The Legs

The legs are attached by the blue rods in the lower middle yellow pieces of the exoskeleton and upper middle yellow pieces of the exoskeleton. The you attach the green and white parts to it as shown in the picture